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  • Optimizing processing and management of large Java data arrays

    - by mikera
    I'm writing some pretty CPU-intensive, concurrent numerical code that will process large amounts of data stored in Java arrays (e.g. lots of double[100000]s). Some of the algorithms might run millions of times over several days so getting maximum steady-state performance is a high priority. In essence, each algorithm is a Java object that has an method API something like: public double[] runMyAlgorithm(double[] inputData); or alternatively a reference could be passed to the array to store the output data: public runMyAlgorithm(double[] inputData, double[] outputData); Given this requirement, I'm trying to determine the optimal strategy for allocating / managing array space. Frequently the algorithms will need large amounts of temporary storage space. They will also take large arrays as input and create large arrays as output. Among the options I am considering are: Always allocate new arrays as local variables whenever they are needed (e.g. new double[100000]). Probably the simplest approach, but will produce a lot of garbage. Pre-allocate temporary arrays and store them as final fields in the algorithm object - big downside would be that this would mean that only one thread could run the algorithm at any one time. Keep pre-allocated temporary arrays in ThreadLocal storage, so that a thread can use a fixed amount of temporary array space whenever it needs it. ThreadLocal would be required since multiple threads will be running the same algorithm simultaneously. Pass around lots of arrays as parameters (including the temporary arrays for the algorithm to use). Not good since it will make the algorithm API extremely ugly if the caller has to be responsible for providing temporary array space.... Allocate extremely large arrays (e.g. double[10000000]) but also provide the algorithm with offsets into the array so that different threads will use a different area of the array independently. Will obviously require some code to manage the offsets and allocation of the array ranges. Any thoughts on which approach would be best (and why)?

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  • C#: Wrong answer when finding "cool" numbers.

    - by user300484
    Hello you all! In my application, a "cool" number is a number that is both a square and a cube, like for example: 64 = 8^2 and 64 = 4^3. My application is supposed to find the number of "cool numbers" between a range given by the user. I wrote my code and the application runs fine, but it is giving me the wrong answer. Can you help me here please? for example: IMPUT 1 100 OUTPUT 1 using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace ConsoleApplication1 { class Program { static void Main(string[] args) { double a = Convert.ToDouble(Console.ReadLine()); // first number in the range double b = Convert.ToDouble(Console.ReadLine()); // second number in the range long x = 0; for (double i = a; i <= b; i++) { double cube = 1.0 / 3.0; double cuad = 1.0 / 2.0; double crt = Math.Pow(i, cube); // cube root double sqrt = Math.Pow(i, cuad); // square root if ((crt * 10) % 10 == 0 || (sqrt * 10) % 10 == 0) // condition to determine if it is a cool number. x++; } Console.WriteLine(x); Console.ReadLine(); } } }

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  • Trouble with custom WPF Panel-derived class

    - by chaiguy
    I'm trying to write a custom Panel class for WPF, by overriding MeasureOverride and ArrangeOverride but, while it's mostly working I'm experiencing one strange problem I can't explain. In particular, after I call Arrange on my child items in ArrangeOverride after figuring out what their sizes should be, they aren't sizing to the size I give to them, and appear to be sizing to the size passed to their Measure method inside MeasureOverride. Am I missing something in how this system is supposed to work? My understanding is that calling Measure simply causes the child to evaluate its DesiredSize based on the supplied availableSize, and shouldn't affect its actual final size. Here is my full code (the Panel, btw, is intended to arrange children in the most space-efficient manner, giving less space to rows that don't need it and splitting remaining space up evenly among the rest--it currently only supports vertical orientation but I plan on adding horizontal once I get it working properly): protected override Size MeasureOverride( Size availableSize ) { foreach ( UIElement child in Children ) child.Measure( availableSize ); return availableSize; } protected override System.Windows.Size ArrangeOverride( System.Windows.Size finalSize ) { double extraSpace = 0.0; var sortedChildren = Children.Cast<UIElement>().OrderBy<UIElement, double>( new Func<UIElement, double>( delegate( UIElement child ) { return child.DesiredSize.Height; } ) ); double remainingSpace = finalSize.Height; double normalSpace = 0.0; int remainingChildren = Children.Count; foreach ( UIElement child in sortedChildren ) { normalSpace = remainingSpace / remainingChildren; if ( child.DesiredSize.Height < normalSpace ) // if == there would be no point continuing as there would be no remaining space remainingSpace -= child.DesiredSize.Height; else { remainingSpace = 0; break; } remainingChildren--; } extraSpace = remainingSpace / Children.Count; double offset = 0.0; foreach ( UIElement child in Children ) { //child.Measure( new Size( finalSize.Width, normalSpace ) ); double value = Math.Min( child.DesiredSize.Height, normalSpace ) + extraSpace; child.Arrange( new Rect( 0, offset, finalSize.Width, value ) ); offset += value; } return finalSize; }

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  • How to extend this design for a generic converter in java?

    - by Jay
    Here is a small currency converter piece of code: public enum CurrencyType { DOLLAR(1), POUND(1.2), RUPEE(.25); private CurrencyType(double factor) { this.factor = factor; } private double factor; public double getFactor() { return factor; } } public class Currency { public Currency(double value, CurrencyType type) { this.value = value; this.type = type; } private CurrencyType type; private double value; public CurrencyType getCurrencyType() { return type; } public double getCurrencyValue() { return value; } public void setCurrenctyValue(double value){ this.value = value; } } public class CurrencyConversion { public static Currency convert(Currency c1, Currency c2) throws Exception { if (c1 != null && c2 != null) { c2.setCurrenctyValue(c1.getCurrencyValue() * c1.getCurrencyType().getFactor() * c2.getCurrencyType().getFactor()); return c2; } else throw new Exception(); } } I would like to improve this code to make it work for different units of conversion, for example: kgs to pounds, miles to kms, etc etc. Something that looks like this: public class ConversionManager<T extends Convertible> { public T convert(T c1, T c2) { //return null; } } Appreciate your ideas and suggestions.

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  • C# - default parameter values from previous parameter

    - by Sagar R. Kothari
    namespace HelloConsole { public class BOX { double height, length, breadth; public BOX() { } // here, I wish to pass 'h' to remaining parameters if not passed // FOLLOWING Gives compilation error. public BOX (double h, double l = h, double b = h) { Console.WriteLine ("Constructor with default parameters"); height = h; length = l; breadth = b; } } } // // BOX a = new BOX(); // default constructor. all okay here. // BOX b = new BOX(10,20,30); // all parameter passed. all okay here. // BOX c = new BOX(10); // Here, I want = length=10, breadth=10,height=10; // BOX d = new BOX(10,20); // Here, I want = length=10, breadth=20,height=10; Question is : 'To achieve above, Is 'constructor overloading' (as follows) is the only option? public BOX(double h) { height = length = breadth = h; } public BOX(double h, double l) { height = breadth = h; length = l; }

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  • rotating a circle in UIView?

    - by senthilmuthu
    HI, i want to draw a circle in DrawRect through context like pie chart(took from tutorial) thorugh UITouch? i have given the code as follows,how can i rotate ? any help please? define PI 3.14159265358979323846 define snapshot_start 360 define snapshot_finish 360 static inline float radians(double degrees) { return degrees * PI / 180; } - (void)drawRect:(CGRect)rect { // Drawing code CGRect parentViewBounds = self.bounds; CGFloat x = CGRectGetWidth(parentViewBounds)/2; CGFloat y = CGRectGetHeight(parentViewBounds)*0.55; // Get the graphics context and clear it CGContextRef ctx = UIGraphicsGetCurrentContext(); CGContextClearRect(ctx, rect); // define stroke color CGContextSetRGBStrokeColor(ctx, 1, 1, 1, 1.0); // define line width CGContextSetLineWidth(ctx, 4.0); // need some values to draw pie charts double snapshotCapacity =20; double rawCapacity = 100; double systemCapacity = 1; int offset = 5; double pie1_start = 315.0; double pie1_finish = snapshotCapacity *360.0/rawCapacity; double system_finish = systemCapacity*360.0/rawCapacity; CGContextSetFillColor(ctx, CGColorGetComponents( [[UIColor greenColor] CGColor])); CGContextMoveToPoint(ctx, x+2*offset, y); CGContextAddArc(ctx, x+2*offset, y, 100, radians(snapshot_start), radians(snapshot_start+snapshot_finish), 0); CGContextClosePath(ctx); CGContextFillPath(ctx); // system capacity CGContextSetFillColor(ctx, CGColorGetComponents( [[UIColor colorWithRed:15 green:165/255 blue:0 alpha:1 ] CGColor])); CGContextMoveToPoint(ctx, x+offset,y); CGContextAddArc(ctx, x+offset, y, 100, radians(snapshot_start+snapshot_finish+offset), radians(snapshot_start+snapshot_finish+system_finish), 0); CGContextClosePath(ctx); CGContextFillPath(ctx); /* data capacity */ CGContextSetFillColor(ctx, CGColorGetComponents( [[UIColor colorWithRed:99/255 green:184/255 blue:255/255 alpha:1 ] CGColor])); CGContextMoveToPoint(ctx, x, y); CGContextAddArc(ctx, x, y, 100, radians(snapshot_start+snapshot_finish+system_finish+offset), radians(snapshot_start), 0); CGContextClosePath(ctx); CGContextFillPath(ctx); }

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  • Java data structure suggestion.

    - by techoverflow
    Hi folks, I am a newbie in this field so please excuse my silly mistakes :) So the issue I am facing is: On my webpage, I am displaying a table. For now my issue is concerned with three columns of the table. First is : Area Code Second is : Zone Code Third is: Value The relationship between these three is: 1 Area Code has 6 different Zone code's and all those 6 Zone codes have corresponding "Value" I need a data structer that would give me the flexibility to get a "Value" for a Zone code, which falls under a particular Area code. I have the same zone codes for all the Area codes: Zone codes are: 111, 222, 333, 444, 555, 666 After surfing your stackoverflow, I thought I can go with this structure: Map<Integer, Map<Integer, Double>> retailPrices = new HashMap<Integer, Map<Integer, Double>>(); Map<Integer, Double> codes = new HashMap<Integer, Double>(); where reatailPrices would hold an Area Code and a Map of Zone code as Key and "Value" as Value. but when I am trying to populate this through a SQL resultset, I am getting the following error: The method put(Integer, Map<Integer,Double>) in the type Map is not applicable for the arguments (Integer, Double) on line: `while(oResult.next()) retailPrices.put((new Integer(oResult.getString("AREA"))), (pegPlPrices.put(new Integer(oResult.getString("ZONE_CODE")), new Double(oResult.getString("VALUE"))))); }` please help me figure out this problem. Am I following the right approach?

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  • Interesting Scala typing solution, doesn't work in 2.7.7?

    - by djc
    I'm trying to build some image algebra code that can work with images (basically a linear pixel buffer + dimensions) that have different types for the pixel. To get this to work, I've defined a parametrized Pixel trait with a few methods that should be able to get used with any Pixel subclass. (For now, I'm only interested in operations that work on the same Pixel type.) Here it is: trait Pixel[T <: Pixel[T]] { def mul(v: Double): T def max(v: T): T def div(v: Double): T def div(v: T): T } Now I define a single Pixel type that has storage based on three doubles (basically RGB 0.0-1.0), I've called it TripleDoublePixel: class TripleDoublePixel(v: Array[Double]) extends Pixel[TripleDoublePixel] { var data: Array[Double] = v def this() = this(Array(0.0, 0.0, 0.0)) def toString(): String = { "(" + data(0) + ", " + data(1) + ", " + data(2) + ")" } def increment(v: TripleDoublePixel) { data(0) += v.data(0) data(1) += v.data(1) data(2) += v.data(2) } def mul(v: Double): TripleDoublePixel = { new TripleDoublePixel(data.map(x => x * v)) } def div(v: Double): TripleDoublePixel = { new TripleDoublePixel(data.map(x => x / v)) } def div(v: TripleDoublePixel): TripleDoublePixel = { var tmp = new Array[Double](3) tmp(0) = data(0) / v.data(0) tmp(1) = data(1) / v.data(1) tmp(2) = data(2) / v.data(2) new TripleDoublePixel(tmp) } def max(v: TripleDoublePixel): TripleDoublePixel = { val lv = data(0) * data(0) + data(1) * data(1) + data(2) * data(2) val vv = v.data(0) * v.data(0) + v.data(1) * v.data(1) + v.data(2) * v.data(2) if (lv > vv) (this) else v } } Now I want to write code to use this, that doesn't have to know what type the pixels are. For example: def idiv[T](a: Image[T], b: Image[T]) { for (i <- 0 until a.data.size) { a.data(i) = a.data(i).div(b.data(i)) } } Unfortunately, this doesn't compile: (fragment of lindet-gen.scala):145: error: value div is not a member of T a.data(i) = a.data(i).div(b.data(i)) I was told in #scala that this worked for someone else, but that was on 2.8. I've tried to get 2.8-rc1 going, but it doesn't compile for me. Is there any way to get this to work in 2.7.7?

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  • Dynamic Array of Objects Sans Vector Class

    - by Connor Black
    I am doing a homework assignment for my summer OO class and we need to write two classes. One is called Sale and the other is called Register. I've written my Sale class; here's the .h file: enum ItemType {BOOK, DVD, SOFTWARE, CREDIT}; class Sale { public: Sale(); // default constructor, // sets numerical member data to 0 void MakeSale(ItemType x, double amt); ItemType Item(); // Returns the type of item in the sale double Price(); // Returns the price of the sale double Tax(); // Returns the amount of tax on the sale double Total(); // Returns the total price of the sale void Display(); // outputs sale info private: double price; // price of item or amount of credit double tax; // amount of sales tax double total; // final price once tax is added in. ItemType item; // transaction type }; For the Register class we need to include a dynamic array of Sale objects in our member data. We cannot use the vector class. How is this done? Here's my 'Register' '.h' class Register{ public: Register(int ident, int amount); ~Register(); int GetID(){return identification;} int GetAmount(){return amountMoney;} void RingUpSale(ItemType item, int basePrice); void ShowLast(); void ShowAll(); void Cancel(); int SalesTax(int n); private: int identification; int amountMoney; };

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  • Pointers to a typed variable in C#: Interfase, Generic, object or Class? (Boxing/Unboxing)

    - by PaulG
    First of all, I apologize if this has been asked a thousand times. I read my C# book, I googled it, but I can't seem to find the answer I am looking for, or I am missing the point big time. I am very confused with the whole boxing/unboxing issue. Say I have fields of different classes, all returning typed variables (e.g. 'double') and I would like to have a variable point to any of these fields. In plain old C I would do something like: double * newVar; newVar = &oldVar; newVar = &anotherVar; ... In C#, it seems I could do an interfase, but would require that all fields be properties and named the same. Breaks apart when one of the properties doesn't have the same name or is not a property. I could also create a generic class returning double, but seems a bit absurd to create a class to represent a 'double', when a 'double' class already exists. If I am not mistaken, it doesn't even need to be generic, could be a simple class returning double. I could create an object and box the typed variable to the newly created object, but then I would have to cast every time I use it. Of course, I always have the unsafe option... but afraid of getting to unknown memory space, divide by zero and bring an end to this world. None of these seem to be the same as the old simple 'double * variable'. Am I missing something here?

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  • Why is this giving me an infinite loop?

    - by Chase Yuan
    I was going through a code used to calculate investments until it has doubled and I received an infinite loop that I can't seem to solve. Can anyone figure out why this is giving me an infinite loop? I've gone through myself but I can't seem to find the problem. The "period" referred is how many times per year the interest is compounded. double account = 0; //declares the variables to be used double base = 0; double interest = 0; double rate = 0; double result = 0; double times = 0; int years = 0; int j; System.out.println("This is a program that calculates interest."); Scanner kbReader = new Scanner(System.in); //enters in all data System.out.print("Enter account balance: "); account = kbReader.nextDouble(); System.out.print("Enter interest rate (as decimal): "); rate = kbReader.nextDouble(); System.out.println(" " + "Years to double" + " " + "Ending balance"); base = account; result = account; for (j=0; j<3; j++){ System.out.print("Enter period: "); times = kbReader.nextDouble(); while (account < base*2){ interest = account * rate / times; account = interest + base; years++; } account = (((int)(account * 100))/100.0); //results System.out.print(" " + i + " " + account + "\n"); account = result; } The code should ask for three "periods", or three different times the entered data is compounded per year (ex annually, monthly, daily etc.) Thanks a lot!

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  • Calling a constructor from method within the same class

    - by Nathan
    I'm new to java and I'm learning about creating object classes. One of my homework assignment requires that I call the constructor at least once within a method of the same object class. I'm getting an error that says The method DoubleMatrix(double[][]) is undefined for the type DoubleMatrix Here's my constructor: public DoubleMatrix(double[][] tempArray) { // Declaration int flag = 0; int cnt; // Statement // check to see if doubArray isn't null and has more than 0 rows if(tempArray == null || tempArray.length < 0) { flag++; } // check to see if each row has the same length if(flag == 0) { for(cnt = 0; cnt <= tempArray.length - 1 || flag != 1; cnt++) { if(tempArray[cnt + 1].length != tempArray[0].length) { flag++; } } } else if(flag == 1) { makeDoubMatrix(1, 1);// call makeDoubMatrix method } }// end constructor 2 Here's the method where I try and call the constructor: public double[][] addMatrix(double[][] tempDoub) { // Declaration double[][] newMatrix; int rCnt, cCnt; //Statement // checking to see if both are of same dimension if(doubMatrix.length == tempDoub.length && doubMatrix[0].length == tempDoub[0].length) { newMatrix = new double[doubMatrix.length][doubMatrix[0].length]; // for loop to add matrix to a new one for(rCnt = 0; rCnt <= doubMatrix.length; rCnt++) { for(cCnt = 0; cCnt <= doubMatrix.length; cCnt++) { newMatrix[rCnt][cCnt] = doubMatrix[rCnt][cCnt] + tempDoub[rCnt][cCnt]; } } } else { newMatrix = new double[0][0]; DoubleMatrix(newMatrix) } return newMatrix; }// end addMatrix method Can someone point me to the right direction and explain why I'm getting an error?

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  • User Input That Involves A ' ' Causes A Substring Out Of Range Error

    - by Greenhouse Gases
    Hi Stackoverflow people. You have already helped me quite a bit but near the end of writing this program I have somewhat of a bug. You see in order to read in city names with a space in from a text file I use a '/' that is then replaced by the program for a ' ' (and when the serializer runs the opposite happens for next time the program is run). The problem is when a user inputs a name too add, search for, or delete that contains a space, for instance 'New York' I get a Debug Assertion Error with a substring out of range expression. I have a feeling it's to do with my correctCase function, or setElementsNull that looks at the string until it experiences a null element in the array, however ' ' is not null so I'm not sure how to fix this and I'm going a bit insane. Any help would be much appreciated. Here is my code: // U08221.cpp : main project file. #include "stdafx.h" #include <_iostream> #include <_string> #include <_fstream> #include <_cmath> using namespace std; class locationNode { public: string nodeCityName; double nodeLati; double nodeLongi; locationNode* Next; locationNode(string nameOf, double lat, double lon) { this->nodeCityName = nameOf; this->nodeLati = lat; this->nodeLongi = lon; this->Next = NULL; } locationNode() // NULL constructor { } void swapProps(locationNode *node2) { locationNode place; place.nodeCityName = this->nodeCityName; place.nodeLati = this->nodeLati; place.nodeLongi = this->nodeLongi; this->nodeCityName = node2->nodeCityName; this->nodeLati = node2->nodeLati; this->nodeLongi = node2->nodeLongi; node2->nodeCityName = place.nodeCityName; node2->nodeLati = place.nodeLati; node2->nodeLongi = place.nodeLongi; } void modify(string name) { this->nodeCityName = name; } void modify(double latlon, int mod) { switch(mod) { case 2: this->nodeLati = latlon; break; case 3: this->nodeLongi = latlon; break; } } void correctCase() // Correct upper and lower case letters of input { int MAX_SIZE = 35; int firstLetVal = this->nodeCityName[0], letVal; int n = 1; // variable for name index from second letter onwards if((this->nodeCityName[0] >90) && (this->nodeCityName[0] < 123)) // First letter is lower case { firstLetVal = firstLetVal - 32; // Capitalise first letter this->nodeCityName[0] = firstLetVal; } while(this->nodeCityName[n] != NULL) { if((this->nodeCityName[n] >= 65) && (this->nodeCityName[n] <= 90)) { if(this->nodeCityName[n - 1] != 32) { letVal = this->nodeCityName[n] + 32; this->nodeCityName[n] = letVal; } } n++; } } }; Here is the main part of the program: // U08221.cpp : main project file. #include "stdafx.h" #include "Locations2.h" #include <_iostream> #include <_string> #include <_fstream> #include <_cmath> using namespace std; #define pi 3.14159265358979323846264338327950288 #define radius 6371 #define gig 1073741824 //size of a gigabyte in bytes int n = 0,x, locationCount = 0, MAX_SIZE = 35 , g = 0, i = 0, modKey = 0, xx; string cityNameInput, alter; char targetCity[35], skipKey = ' '; double lat1, lon1, lat2, lon2, dist, dummy, modVal, result; bool acceptedInput = false, match = false, nodeExists = false;// note: addLocation(), set to true to enable user input as opposed to txt file locationNode *temp, *temp2, *example, *seek, *bridge, *start_ptr = NULL; class Menu { int junction; public: /* Convert decimal degrees to radians */ public: void setElementsNull(char cityParam[]) { int y=0; while(cityParam[y] != NULL) { y++; } while(y < MAX_SIZE) { cityParam[y] = NULL; y++; } } void correctCase(string name) // Correct upper and lower case letters of input { int MAX_SIZE = 35; int firstLetVal = name[0], letVal; int n = 1; // variable for name index from second letter onwards if((name[0] >90) && (name[0] < 123)) // First letter is lower case { firstLetVal = firstLetVal - 32; // Capitalise first letter name[0] = firstLetVal; } while(name[n] != NULL) { if((name[n] >= 65) && (name[n] <= 90)) { letVal = name[n] + 32; name[n] = letVal; } n++; } for(n = 0; targetCity[n] != NULL; n++) { targetCity[n] = name[n]; } } bool nodeExistTest(char targetCity[]) // see if entry is present in the database { match = false; seek = start_ptr; int letters = 0, letters2 = 0, x = 0, y = 0; while(targetCity[y] != NULL) { letters2++; y++; } while(x <= locationCount) // locationCount is number of entries currently in list { y=0, letters = 0; while(seek->nodeCityName[y] != NULL) // count letters in the current name { letters++; y++; } if(letters == letters2) // same amount of letters in the name { y = 0; while(y <= letters) // compare each letter against one another { if(targetCity[y] == seek->nodeCityName[y]) { match = true; y++; } else { match = false; y = letters + 1; // no match, terminate comparison } } } if(match) { x = locationCount + 1; //found match so terminate loop } else{ if(seek->Next != NULL) { bridge = seek; seek = seek->Next; x++; } else { x = locationCount + 1; // end of list so terminate loop } } } return match; } double deg2rad(double deg) { return (deg * pi / 180); } /* Convert radians to decimal degrees */ double rad2deg(double rad) { return (rad * 180 / pi); } /* Do the calculation */ double distance(double lat1, double lon1, double lat2, double lon2, double dist) { dist = sin(deg2rad(lat1)) * sin(deg2rad(lat2)) + cos(deg2rad(lat1)) * cos(deg2rad(lat2)) * cos(deg2rad(lon1 - lon2)); dist = acos(dist); dist = rad2deg(dist); dist = (radius * pi * dist) / 180; return dist; } void serialise() { // Serialize to format that can be written to text file fstream outfile; outfile.open("locations.txt",ios::out); temp = start_ptr; do { for(xx = 0; temp->nodeCityName[xx] != NULL; xx++) { if(temp->nodeCityName[xx] == 32) { temp->nodeCityName[xx] = 47; } } outfile << endl << temp->nodeCityName<< " "; outfile<<temp->nodeLati<< " "; outfile<<temp->nodeLongi; temp = temp->Next; }while(temp != NULL); outfile.close(); } void sortList() // do this { int changes = 1; locationNode *node1, *node2; while(changes > 0) // while changes are still being made to the list execute { node1 = start_ptr; node2 = node1->Next; changes = 0; do { xx = 1; if(node1->nodeCityName[0] > node2->nodeCityName[0]) //compare first letter of name with next in list { node1->swapProps(node2); // should come after the next in the list changes++; } else if(node1->nodeCityName[0] == node2->nodeCityName[0]) // if same first letter { while(node1->nodeCityName[xx] == node2->nodeCityName[xx]) // check next letter of name { if((node1->nodeCityName[xx + 1] != NULL) && (node2->nodeCityName[xx + 1] != NULL)) // check next letter until not the same { xx++; } else break; } if(node1->nodeCityName[xx] > node2->nodeCityName[xx]) { node1->swapProps(node2); // should come after the next in the list changes++; } } node1 = node2; node2 = node2->Next; // move to next pair in list } while(node2 != NULL); } } void initialise() { cout << "Populating List..."; ifstream inputFile; inputFile.open ("locations.txt", ios::in); char inputName[35] = " "; double inputLati = 0, inputLongi = 0; //temp = new locationNode(inputName, inputLati, inputLongi); do { inputFile.get(inputName, 35, ' '); inputFile >> inputLati; inputFile >> inputLongi; if(inputName[0] == 10 || 13) //remove linefeed from input { for(int i = 0; inputName[i] != NULL; i++) { inputName[i] = inputName[i + 1]; } } for(xx = 0; inputName[xx] != NULL; xx++) { if(inputName[xx] == 47) // if it is a '/' { inputName[xx] = 32; // replace it for a space } } temp = new locationNode(inputName, inputLati, inputLongi); if(start_ptr == NULL){ // if list is currently empty, start_ptr will point to this node start_ptr = temp; } else { temp2 = start_ptr; // We know this is not NULL - list not empty! while (temp2->Next != NULL) { temp2 = temp2->Next; // Move to next link in chain until reach end of list } temp2->Next = temp; } ++locationCount; // increment counter for number of records in list } while(!inputFile.eof()); cout << "Successful!" << endl << "List contains: " << locationCount << " entries" << endl; inputFile.close(); cout << endl << "*******************************************************************" << endl << "DISTANCE CALCULATOR v2.0\tAuthors: Darius Hodaei, Joe Clifton" << endl; } void menuInput() { char menuChoice = ' '; while(menuChoice != 'Q') { // Menu if(skipKey != 'X') // This is set by case 'S' below if a searched term does not exist but wants to be added { cout << endl << "*******************************************************************" << endl; cout << "Please enter a choice for the menu..." << endl << endl; cout << "(P) To print out the list" << endl << "(O) To order the list alphabetically" << endl << "(A) To add a location" << endl << "(D) To delete a record" << endl << "(C) To calculate distance between two points" << endl << "(S) To search for a location in the list" << endl << "(M) To check memory usage" << endl << "(U) To update a record" << endl << "(Q) To quit" << endl; cout << endl << "*******************************************************************" << endl; cin >> menuChoice; if(menuChoice >= 97) { menuChoice = menuChoice - 32; // Turn the lower case letter into an upper case letter } } skipKey = ' '; //Reset skipKey so that it does not skip the menu switch(menuChoice) { case 'P': temp = start_ptr; // set temp to the start of the list do { if (temp == NULL) { cout << "You have reached the end of the database" << endl; } else { // Display details for what temp points to at that stage cout << "Location : " << temp->nodeCityName << endl; cout << "Latitude : " << temp->nodeLati << endl; cout << "Longitude : " << temp->nodeLongi << endl; cout << endl; // Move on to next locationNode if one exists temp = temp->Next; } } while (temp != NULL); break; case 'O': { sortList(); // pass by reference??? cout << "List reordered alphabetically" << endl; } break; case 'A': char cityName[35]; double lati, longi; cout << endl << "Enter the name of the location: "; cin >> cityName; for(xx = 0; cityName[xx] != NULL; xx++) { if(cityName[xx] == 47) // if it is a '/' { cityName[xx] = 32; // replace it for a space } } if(!nodeExistTest(cityName)) { cout << endl << "Please enter the latitude value for this location: "; cin >> lati; cout << endl << "Please enter the longitude value for this location: "; cin >> longi; cout << endl; temp = new locationNode(cityName, lati, longi); temp->correctCase(); //start_ptr allignment if(start_ptr == NULL){ // if list is currently empty, start_ptr will point to this node start_ptr = temp; } else { temp2 = start_ptr; // We know this is not NULL - list not empty! while (temp2->Next != NULL) { temp2 = temp2->Next; // Move to next link in chain until reach end of list } temp2->Next = temp; } ++locationCount; // increment counter for number of records in list cout << "Location sucessfully added to the database! There are " << locationCount << " location(s) stored" << endl; } else { cout << "Node is already present in the list and so cannot be added again" << endl; } break; case 'D': { junction = 0; locationNode *place; cout << "Enter the name of the city you wish to remove" << endl; cin >> targetCity; setElementsNull(targetCity); correctCase(targetCity); for(xx = 0; targetCity[xx] != NULL; xx++) { if(targetCity[xx] == 47) { targetCity[xx] = 32; } } if(nodeExistTest(targetCity)) //if this node does exist { if(seek == start_ptr) // if it is the first in the list { junction = 1; } if(seek->Next == NULL) // if it is last in the list { junction = 2; } switch(junction) // will alter list accordingly dependant on where the searched for link is { case 1: start_ptr = start_ptr->Next; delete seek; --locationCount; break; case 2: place = seek; seek = bridge; seek->Next = NULL; delete place; --locationCount; break; default: bridge->Next = seek->Next; delete seek; --locationCount; break; } cout << endl << "Link deleted. There are now " << locationCount << " locations." << endl; } else { cout << "That entry does not currently exist" << endl << endl << endl; } } break; case 'C': { char city1[35], city2[35]; cout << "Enter the first city name" << endl; cin >> city1; setElementsNull(city1); correctCase(targetCity); if(nodeExistTest(city1)) { lat1 = seek->nodeLati; lon1 = seek->nodeLongi; cout << "Lati = " << seek->nodeLati << endl << "Longi = " << seek->nodeLongi << endl << endl; } cout << "Enter the second city name" << endl; cin >> city2; setElementsNull(city2); correctCase(targetCity); if(nodeExistTest(city2)) { lat2 = seek->nodeLati; lon2 = seek->nodeLongi; cout << "Lati = " << seek->nodeLati << endl << "Longi = " << seek->nodeLongi << endl << endl; } result = distance (lat1, lon1, lat2, lon2, dist); cout << "The distance between these two locations is " << result << " kilometres." << endl; } break; case 'S': { char choice; cout << "Enter search term..." << endl; cin >> targetCity; setElementsNull(targetCity); correctCase(targetCity); if(nodeExistTest(targetCity)) { cout << "Latitude: " << seek->nodeLati << endl << "Longitude: " << seek->nodeLongi << endl; } else { cout << "Sorry, that city is not currently present in the list." << endl << "Would you like to add this city now Y/N?" << endl; cin >> choice; /*while(choice != ('Y' || 'N')) { cout << "Please enter a valid choice..." << endl; cin >> choice; }*/ switch(choice) { case 'Y': skipKey = 'X'; menuChoice = 'A'; break; case 'N': break; default : cout << "Invalid choice" << endl; break; } } break; } case 'M': { cout << "Locations currently stored: " << locationCount << endl << "Memory used for this: " << (sizeof(start_ptr) * locationCount) << " bytes" << endl << endl << "You can store " << ((gig - (sizeof(start_ptr) * locationCount)) / sizeof(start_ptr)) << " more locations" << endl ; break; } case 'U': { cout << "Enter the name of the Location you would like to update: "; cin >> targetCity; setElementsNull(targetCity); correctCase(targetCity); if(nodeExistTest(targetCity)) { cout << "Select (1) to alter City Name, (2) to alter Longitude, (3) to alter Latitude" << endl; cin >> modKey; switch(modKey) { case 1: cout << "Enter the new name: "; cin >> alter; cout << endl; seek->modify(alter); break; case 2: cout << "Enter the new latitude: "; cin >> modVal; cout << endl; seek->modify(modVal, modKey); break; case 3: cout << "Enter the new longitude: "; cin >> modVal; cout << endl; seek->modify(modVal, modKey); break; default: break; } } else cout << "Location not found" << endl; break; } } } } }; int main(array<System::String ^> ^args) { Menu mm; //mm.initialise(); mm.menuInput(); mm.serialise(); }

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  • Overriding Object.Equals() instance method in C#; now Code Analysis / FxCop warning CA2218: "should

    - by Chris W. Rea
    I've got a complex class in my C# project on which I want to be able to do equality tests. It is not a trivial class; it contains a variety of scalar properties as well as references to other objects and collections (e.g. IDictionary). For what it's worth, my class is sealed. To enable a performance optimization elsewhere in my system (an optimization that avoids a costly network round-trip), I need to be able to compare instances of these objects to each other for equality – other than the built-in reference equality – and so I'm overriding the Object.Equals() instance method. However, now that I've done that, Visual Studio 2008's Code Analysis a.k.a. FxCop, which I keep enabled by default, is raising the following warning: warning : CA2218 : Microsoft.Usage : Since 'MySuperDuperClass' redefines Equals, it should also redefine GetHashCode. I think I understand the rationale for this warning: If I am going to be using such objects as the key in a collection, the hash code is important. i.e. see this question. However, I am not going to be using these objects as the key in a collection. Ever. Feeling justified to suppress the warning, I looked up code CA2218 in the MSDN documentation to get the full name of the warning so I could apply a SuppressMessage attribute to my class as follows: [SuppressMessage("Microsoft.Naming", "CA2218:OverrideGetHashCodeOnOverridingEquals", Justification="This class is not to be used as key in a hashtable.")] However, while reading further, I noticed the following: How to Fix Violations To fix a violation of this rule, provide an implementation of GetHashCode. For a pair of objects of the same type, you must ensure that the implementation returns the same value if your implementation of Equals returns true for the pair. When to Suppress Warnings ----- Do not suppress a warning from this rule. [arrow & emphasis mine] So, I'd like to know: Why shouldn't I suppress this warning as I was planning to? Doesn't my case warrant suppression? I don't want to code up an implementation of GetHashCode() for this object that will never get called, since my object will never be the key in a collection. If I wanted to be pedantic, instead of suppressing, would it be more reasonable for me to override GetHashCode() with an implementation that throws a NotImplementedException? Update: I just looked this subject up again in Bill Wagner's good book Effective C#, and he states in "Item 10: Understand the Pitfalls of GetHashCode()": If you're defining a type that won't ever be used as the key in a container, this won't matter. Types that represent window controls, web page controls, or database connections are unlikely to be used as keys in a collection. In those cases, do nothing. All reference types will have a hash code that is correct, even if it is very inefficient. [...] In most types that you create, the best approach is to avoid the existence of GetHashCode() entirely. ... that's where I originally got this idea that I need not be concerned about GetHashCode() always.

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  • How do I create an instance of this class in Android?

    - by Lloyd Banks
    I was wondering if it is possible to create an instance of this class (from the link, which creates a listview) from another class so that I can call on either lazyadapter.java or customizedlistview.java (not sure which one) to inflate that same listview. Is this possible? This is what I tried (obviously incorrect): CustomizedListView clv = new CustomizedListView(); clv.onCreate(...); source: http://www.androidhive.info/2012/02/android-custom-listview-with-image-and-text/ LazyAdapter.java import java.util.ArrayList; import java.util.HashMap; import android.app.Activity; import android.content.Context; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.BaseAdapter; import android.widget.ImageView; import android.widget.TextView; public class LazyAdapter extends BaseAdapter { private Activity activity; private ArrayList&lt;HashMap&lt;String, String&gt;&gt; data; private static LayoutInflater inflater=null; public ImageLoader imageLoader; public LazyAdapter(Activity a, ArrayList&lt;HashMap&lt;String, String&gt;&gt; d) { activity = a; data=d; inflater = (LayoutInflater)activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE); imageLoader=new ImageLoader(activity.getApplicationContext()); } public int getCount() { return data.size(); } public Object getItem(int position) { return position; } public long getItemId(int position) { return position; } public View getView(int position, View convertView, ViewGroup parent) { View vi=convertView; if(convertView==null) vi = inflater.inflate(R.layout.list_row, null); TextView title = (TextView)vi.findViewById(R.id.title); // title TextView artist = (TextView)vi.findViewById(R.id.artist); // artist name TextView duration = (TextView)vi.findViewById(R.id.duration); // duration ImageView thumb_image=(ImageView)vi.findViewById(R.id.list_image); // thumb image HashMap&lt;String, String&gt; song = new HashMap&lt;String, String&gt;(); song = data.get(position); // Setting all values in listview title.setText(song.get(CustomizedListView.KEY_TITLE)); artist.setText(song.get(CustomizedListView.KEY_ARTIST)); duration.setText(song.get(CustomizedListView.KEY_DURATION)); imageLoader.DisplayImage(song.get(CustomizedListView.KEY_THUMB_URL), thumb_image); return vi; } } CustomizedListView.java import java.util.ArrayList; import java.util.HashMap; import org.w3c.dom.Document; import org.w3c.dom.Element; import org.w3c.dom.NodeList; import android.app.Activity; import android.os.Bundle; import android.view.View; import android.widget.AdapterView; import android.widget.AdapterView.OnItemClickListener; import android.widget.ListView; public class CustomizedListView extends Activity { // All static variables static final String URL = "http://api.androidhive.info/music/music.xml"; // XML node keys static final String KEY_SONG = "song"; // parent node static final String KEY_ID = "id"; static final String KEY_TITLE = "title"; static final String KEY_ARTIST = "artist"; static final String KEY_DURATION = "duration"; static final String KEY_THUMB_URL = "thumb_url"; ListView list; LazyAdapter adapter; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); ArrayList&lt;HashMap&lt;String, String&gt;&gt; songsList = new ArrayList&lt;HashMap&lt;String, String&gt;&gt;(); XMLParser parser = new XMLParser(); String xml = parser.getXmlFromUrl(URL); // getting XML from URL Document doc = parser.getDomElement(xml); // getting DOM element NodeList nl = doc.getElementsByTagName(KEY_SONG); // looping through all song nodes &lt;song&gt; for (int i = 0; i &lt; nl.getLength(); i++) { // creating new HashMap HashMap&lt;String, String&gt; map = new HashMap&lt;String, String&gt;(); Element e = (Element) nl.item(i); // adding each child node to HashMap key =&gt; value map.put(KEY_ID, parser.getValue(e, KEY_ID)); map.put(KEY_TITLE, parser.getValue(e, KEY_TITLE)); map.put(KEY_ARTIST, parser.getValue(e, KEY_ARTIST)); map.put(KEY_DURATION, parser.getValue(e, KEY_DURATION)); map.put(KEY_THUMB_URL, parser.getValue(e, KEY_THUMB_URL)); // adding HashList to ArrayList songsList.add(map); } list=(ListView)findViewById(R.id.list); // Getting adapter by passing xml data ArrayList adapter=new LazyAdapter(this, songsList); list.setAdapter(adapter); // Click event for single list row list.setOnItemClickListener(new OnItemClickListener() { @Override public void onItemClick(AdapterView&lt;?&gt; parent, View view, int position, long id) { } }); } }

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  • Why is insertion into my tree faster on sorted input than random input?

    - by Juliet
    Now I've always heard binary search trees are faster to build from randomly selected data than ordered data, simply because ordered data requires explicit rebalancing to keep the tree height at a minimum. Recently I implemented an immutable treap, a special kind of binary search tree which uses randomization to keep itself relatively balanced. In contrast to what I expected, I found I can consistently build a treap about 2x faster and generally better balanced from ordered data than unordered data -- and I have no idea why. Here's my treap implementation: http://pastebin.com/VAfSJRwZ And here's a test program: using System; using System.Collections.Generic; using System.Linq; using System.Diagnostics; namespace ConsoleApplication1 { class Program { static Random rnd = new Random(); const int ITERATION_COUNT = 20; static void Main(string[] args) { List<double> rndTimes = new List<double>(); List<double> orderedTimes = new List<double>(); rndTimes.Add(TimeIt(50, RandomInsert)); rndTimes.Add(TimeIt(100, RandomInsert)); rndTimes.Add(TimeIt(200, RandomInsert)); rndTimes.Add(TimeIt(400, RandomInsert)); rndTimes.Add(TimeIt(800, RandomInsert)); rndTimes.Add(TimeIt(1000, RandomInsert)); rndTimes.Add(TimeIt(2000, RandomInsert)); rndTimes.Add(TimeIt(4000, RandomInsert)); rndTimes.Add(TimeIt(8000, RandomInsert)); rndTimes.Add(TimeIt(16000, RandomInsert)); rndTimes.Add(TimeIt(32000, RandomInsert)); rndTimes.Add(TimeIt(64000, RandomInsert)); rndTimes.Add(TimeIt(128000, RandomInsert)); string rndTimesAsString = string.Join("\n", rndTimes.Select(x => x.ToString()).ToArray()); orderedTimes.Add(TimeIt(50, OrderedInsert)); orderedTimes.Add(TimeIt(100, OrderedInsert)); orderedTimes.Add(TimeIt(200, OrderedInsert)); orderedTimes.Add(TimeIt(400, OrderedInsert)); orderedTimes.Add(TimeIt(800, OrderedInsert)); orderedTimes.Add(TimeIt(1000, OrderedInsert)); orderedTimes.Add(TimeIt(2000, OrderedInsert)); orderedTimes.Add(TimeIt(4000, OrderedInsert)); orderedTimes.Add(TimeIt(8000, OrderedInsert)); orderedTimes.Add(TimeIt(16000, OrderedInsert)); orderedTimes.Add(TimeIt(32000, OrderedInsert)); orderedTimes.Add(TimeIt(64000, OrderedInsert)); orderedTimes.Add(TimeIt(128000, OrderedInsert)); string orderedTimesAsString = string.Join("\n", orderedTimes.Select(x => x.ToString()).ToArray()); Console.WriteLine("Done"); } static double TimeIt(int insertCount, Action<int> f) { Console.WriteLine("TimeIt({0}, {1})", insertCount, f.Method.Name); List<double> times = new List<double>(); for (int i = 0; i < ITERATION_COUNT; i++) { Stopwatch sw = Stopwatch.StartNew(); f(insertCount); sw.Stop(); times.Add(sw.Elapsed.TotalMilliseconds); } return times.Average(); } static void RandomInsert(int insertCount) { Treap<double> tree = new Treap<double>((x, y) => x.CompareTo(y)); for (int i = 0; i < insertCount; i++) { tree = tree.Insert(rnd.NextDouble()); } } static void OrderedInsert(int insertCount) { Treap<double> tree = new Treap<double>((x, y) => x.CompareTo(y)); for(int i = 0; i < insertCount; i++) { tree = tree.Insert(i + rnd.NextDouble()); } } } } And here's a chart comparing random and ordered insertion times in milliseconds: Insertions Random Ordered RandomTime / OrderedTime 50 1.031665 0.261585 3.94 100 0.544345 1.377155 0.4 200 1.268320 0.734570 1.73 400 2.765555 1.639150 1.69 800 6.089700 3.558350 1.71 1000 7.855150 4.704190 1.67 2000 17.852000 12.554065 1.42 4000 40.157340 22.474445 1.79 8000 88.375430 48.364265 1.83 16000 197.524000 109.082200 1.81 32000 459.277050 238.154405 1.93 64000 1055.508875 512.020310 2.06 128000 2481.694230 1107.980425 2.24 I don't see anything in the code which makes ordered input asymptotically faster than unordered input, so I'm at a loss to explain the difference. Why is it so much faster to build a treap from ordered input than random input?

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  • ArrayList access

    - by Ricky McQuesten
    So once again I have a question about this program. I want to store transactions that are made in an arraylist and then have an option in the case menu where I can print out those that are stored. I have been researching online and have been unable to find a solution to this, so is this possible and how would I go about doing this? I also want to attach a timestamp to each transaction as well. Here is the code I have so far. So my question is how would I add a timestamp to each withdrawal or deposit, and how would I store each transaction in array list? import java.util.*; public class BankAccount extends Money { //inheritence static String name; public static int acctNum; public static double balance, amount; BankAccount(String name, int accNo, double bal) { this.name = name; this.acctNum = accNo; this.balance = bal; } void display() { System.out.println("Your Name:" + name); System.out.println("Your Account Number:" + acctNum); System.out.println("Your Current Account Balance:" + Money.getBalance()); } void displayBalance() { System.out.println("Balance:" + balance); } } import java.util.Scanner; /** * * @author Ricky */ public class Money { public static int accountNumber; public static double balance; static double amount; static String name; public void setDeposit(double amount) { balance = balance + amount; if (amount < 0) { System.out.println("Invalid"); } } public double getDeposit() { return 1; } public void setBalance(double b) { balance = b; } public static double getBalance() { return balance; } public void setWithdraw(double amount) { if (balance < amount) { System.out.println("Not enough funds."); } else if(amount < 0) { System.out.println("Invalid"); } else { balance = balance - amount; } } public double getWithdraw() { return 1; } } import java.util.*; public class Client { public static void main(String args[]) { int n = 0; int count; String trans; ArrayList<String> transaction= new ArrayList<String>(n); Scanner input = new Scanner(System.in); System.out.println("Welcome to First National Bank"); System.out.println("Please enter your name: "); String cusName = input.nextLine(); System.out.println("You will now be assigned an account number."); Random randomGenerator = new Random(); int accNo = randomGenerator.nextInt(100000); //random number System.out.println("Your account number is: " + accNo); System.out.println("Please enter your initial account balance: "); Double balance = input.nextDouble(); BankAccount b1 = new BankAccount(cusName, accNo, balance); b1.setBalance(balance); int menu; /*System.out.println("Menu"); System.out.println("1. Deposit Amount"); System.out.println("2. Withdraw Amount"); System.out.println("3. Display Information"); System.out.println("4. Exit");*/ boolean quit = false; do { System.out.println("*******Menu*******"); System.out.println("1. Deposit Amount"); // menu to take input from user System.out.println("2. Withdraw Amount"); System.out.println("3. Display Information"); System.out.println("4. Exit"); System.out.print("Please enter your choice: "); menu = input.nextInt(); switch (menu) { case 1: System.out.print("Enter depost amount:"); b1.setDeposit(input.nextDouble()); b1.getDeposit(); transaction.add(trans); break; case 2: System.out.println("Current Account Balance=" + b1.getBalance()); System.out.print("Enter withdrawal amount:"); b1.setWithdraw(input.nextDouble()); b1.getWithdraw(); transaction.add(trans); break; // switch statments to do a loop case 3: b1.display(); break; case 4: quit = true; break; } } while (!quit); } } public class Date { static Date time = new Date(); }

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  • Pass a Delphi class to a C++ function/method that expects a class with __thiscall methods.

    - by Alan G.
    I have some MSVC++ compiled DLL's for which I have created COM-like (lite) interfaces (abstract Delphi classes). Some of those classes have methods that need pointers to objects. These C++ methods are declared with the __thiscall calling convention (which I cannot change), which is just like __stdcall, except a this pointer is passed on the ECX register. I create the class instance in Delphi, then pass it on to the C++ method. I can set breakpoints in Delphi and see it hitting the exposed __stdcall methods in my Delphi class, but soon I get a STATUS_STACK_BUFFER_OVERRUN and the app has to exit. Is it possible to emulate/deal with __thiscall on the Delphi side of things? If I pass an object instantiated by the C++ system then all is good, and that object's methods are called (as would be expected), but this is useless - I need to pass Delphi objects. Edit 2010-04-19 18:12 This is what happens in more detail: The first method called (setLabel) exits with no error (though its a stub method). The second method called (init), enters then dies when it attempts to read the vol parameter. C++ Side #define SHAPES_EXPORT __declspec(dllexport) // just to show the value class SHAPES_EXPORT CBox { public: virtual ~CBox() {} virtual void init(double volume) = 0; virtual void grow(double amount) = 0; virtual void shrink(double amount) = 0; virtual void setID(int ID = 0) = 0; virtual void setLabel(const char* text) = 0; }; Delphi Side IBox = class public procedure destroyBox; virtual; stdcall; abstract; procedure init(vol: Double); virtual; stdcall; abstract; procedure grow(amount: Double); virtual; stdcall; abstract; procedure shrink(amount: Double); virtual; stdcall; abstract; procedure setID(val: Integer); virtual; stdcall; abstract; procedure setLabel(text: PChar); virtual; stdcall; abstract; end; TMyBox = class(IBox) protected FVolume: Double; FID: Integer; FLabel: String; // public constructor Create; destructor Destroy; override; // BEGIN Virtual Method implementation procedure destroyBox; override; stdcall; // empty - Dont need/want C++ to manage my Delphi objects, just call their methods procedure init(vol: Double); override; stdcall; // FVolume := vol; procedure grow(amount: Double); override; stdcall; // Inc(FVolume, amount); procedure shrink(amount: Double); override; stdcall; // Dec(FVolume, amount); procedure setID(val: Integer); override; stdcall; // FID := val; procedure setLabel(text: PChar); override; stdcall; // Stub method; empty. // END Virtual Method implementation property Volume: Double read FVolume; property ID: Integer read FID; property Label: String read FLabel; end; I would have half expected using stdcall alone to work, but something is messing up, not sure what, perhaps something to do with the ECX register being used? Help would be greatly appreciated. Edit 2010-04-19 17:42 Could it be that the ECX register needs to be preserved on entry and restored once the function exits? Is the this pointer required by C++? I'm probably just reaching at the moment based on some intense Google searches. I found something related, but it seems to be dealing with the reverse of this issue.

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  • Referencing ASP.net textbox data in JavaScripts

    - by GoldenEarring
    I'm interested in making an interactive 3D pie chart using JavaScript and ASP.net controls for a webpage. Essentially, I want to make an interactive version of the chart here: https://google-developers.appspot.com/chart/interactive/docs/gallery/piechart#3D I want to have 5 ASP.net textboxes where the user enters data and then submits it, and the chart adjusts according to what the user enters. I understand using ASP.net controls with JS is probably not the most effective way to go about it, but I would really appreciate if someone could share how doing this would be possible. I really don't know where to begin. Thanks for any help! <%@ Page Language="C#" %> <!DOCTYPE html> <script runat="server"> void btn1_Click(object sender, EventArgs e) { double s = 0.0; double b = 0; double g = 0.0f; double c = 0.0f; double h = 0.0f; s = double.Parse(txtWork.Text); b = double.Parse(txtEat.Text); g = double.Parse(txtCommute.Text); c = double.Parse(txtWatchTV.Text); h = double.Parse(txtSleep.Text); double total = s + b + g + c + h; if (total != 24) { lblError.Text = "Warning! A day has 24 hours"; } if (total == 24) { lblError.Text = string.Empty; } } </script> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title></title> <script type="text/javascript" src="https://www.google.com/jsapi"></script> <script type="text/javascript"> google.load("visualization", "1", { packages: ["corechart"] }); google.setOnLoadCallback(drawChart); function drawChart() { var data = google.visualization.arrayToDataTable([ ['Task', 'Hours per Day'], ['Work', 11], ['Eat', 2], ['Commute', 2], ['Watch TV', 2], ['Sleep', 7] ]); var options = { title: 'My Daily Activities', is3D: true, }; var chart = new google.visualization.PieChart(document.getElementById('piechart_3d')); chart.draw(data, options); } var data = new google.visualization.DataTable(); var txtWork = document.getElementById('<%=txtWork.ClientID%>') txtEat = document.getElementById('<%=txtEat.ClientID%>') txtCommute = document.getElementById('<%=txtCommute.ClientID%>') txtWatchTV = document.getElementById('<%=txtWatchTV.ClientID%>') txtSleep = document.getElementById('<%=txtSleep.ClientID%>'); var workvalue = parseInt(txtWork, 10) var eatvalue = parseInt(txtEat, 10) var commutevalue = parseInt(txtCommute, 10) var watchtvvalue = parseInt(txtWatchTV, 10) var sleepvalue = parseInt(txtSleep, 10) // Declare columns data.addColumn('string', 'Task'); data.addColumn('Number', 'Hours per day'); // Add data. data.addRows([ ['Work', workvalue], ['Eat', eatvalue], ['Commute', commutevalue], ['Watch TV', watchtvvalue], ['Sleep', sleepvalue], ]); </script> </head> <body> <form id="form1" runat="server"> <div id="piechart_3d" style="width: 900px; height: 500px;"> </div> <asp:Label ID="lblError" runat="server" Font-Size="X-Large" Font-Bold="true" /> <table> <tr> <td>Work:</td> <td><asp:TextBox ID="txtWork" Text="11" runat="server" /></td> </tr> <tr> <td>Eat:</td> <td><asp:TextBox ID="txtEat" text="2" runat="server" /></td> </tr> <tr> <td>Commute:</td> <td><asp:TextBox ID="txtCommute" Text="2" runat="server" /></td> </tr> <tr> <td>Watch TV:</td> <td><asp:TextBox ID="txtWatchTV" Text="2" runat="server" /></td> </tr> <tr> <td>Sleep:</td> <td><asp:TextBox ID="txtSleep" Text="7" runat="server" /></td> </tr> </table> <br /> <br /> <asp:Button ID="btn1" text="Draw 3D PieChart" runat="server" OnClick="btn1_Click" /> </form> </body> </html>

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  • Connecting multiple ColdFusion 10 instances to a single Apache 2.2 server

    - by Adam Cameron
    This is on Windows 7 Home Premium edition. I have got two ColdFusion 10 (updater 2) instances: "cfusion" (the default one), and "scratch". I have got a single instance of Apache 2.2 running. Within Apache, I have set up two virtual hosts, each of which needs to be served by a different ColdFusion instance. Each of the CF instances serves files fine via Tomcat's internal web server. Apache serves vanilla HTML files fine too. So both CF instances, and both virtual hosts separately work OK. I can get wsconfig.exe to connect either one of the CF instances to the Apache server, and serve CF files via Apache & that instance. However I cannot find a way of connecting the second CF instance to Apache as well, so that both CF instances are conected, each serving one of the virtual hosts. WSConfig doesn't seem to understand the notion of "multiple CF instances", and the changes it makes to the httpd.conf (via mod_jk.conf) does not seem to be implemented in such a way as to accommodate multiple CF instances talking to a single Apache instance, or multiple virtual hosts. I freely admit to not being confident enough with how mod_jk (or even really httpd.conf) works to be able to guess if I can change stuff to make it work. If I try to add the second CF instance using WSConfig, I just get a message "the web server is already configured for ColdFusion". Be that as it may... not the instance of ColdFusion I want to connect it to! If I remove the existing connector to whichever instance is already connected, I can then connect the other one no problems. Not that this helps, but it demonstrates that the CF instance can connect to Apache. This all used to be fairly straight fwd under older versions of CF and JRun :-( The only docs I have found are on the "Connect multiple Apache virtual hosts on a web server to a single ColdFusion server" page, but that specifically only deals with a single CF instance. There is no equivalent page for multiple CF instances. I'm kinda hoping I can move some of the mod_jk config into my virtual host entries in httpd-vhosts.conf (this is how it used to work for JRun), but I've no idea what to put where. I think I've covered all the necessary info here? If not, sing out and I'll add more. Thanks. PS: tried to specifically tag this as "ColdFusion-10" as the answer will be different from previous CF versions, but it won't let me cos my rep on this site is too low (odd how it doesn't consider my rep from other S/O sites...). If someone with sufficient rep can add it, that'd be cool: it's probably a valid tag to have. Ta.

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  • Divide and Conquer Algo to find maximum difference between two ordered elements

    - by instance
    Given an array arr[] of integers, find out the difference between any two elements such that larger element appears after the smaller number in arr[]. Examples: If array is [2, 3, 10, 6, 4, 8, 1, 7] then returned value should be 8 (Diff between 10 and 2). If array is [ 7, 9, 5, 6, 3, 2 ] then returned value should be 2 (Diff between 7 and 9) My Algorithm: I thought of using D&C algorithm. Explanation 2, 3, 10, 6, 4, 8, 1, 7 then 2,3,10,6 and 4,8,1,7 then 2,3 and 10,6 and 4,8 and 1,7 then 2 and 3 10 and 6 4 and 8 1 and 7 Here as these elements will remain in same order, i will get the maximum difference, here it's 6. Now i will move back to merege these arrays and again find the difference between minimum of first block and maximum of second block and keep doing this till end. I am not able to implement this in my code. can anyone please provide a pseudo code for this?

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  • Best way to implement a data structure in PHP ?

    - by Double Gras
    Hi, I want to use some kind of data structure in PHP (5.2), mainly in order to not pollute the global namespace. I think about two approaches, using an array or a class. Could you tell me which approach is better ? Thanks $SQL_PARAMETERS = array ( 'server' => '127.0.0.1', 'login' => 'root'); class SqlParameters { const SERVER = '127.0.0.1'; const LOGIN = 'root'; } echo $SQL_PARAMETERS['server']; echo SqlParameters::SERVER;

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  • A simple Dynamic Proxy

    - by Abhijeet Patel
    Frameworks such as EF4 and MOQ do what most developers consider "dark magic". For instance in EF4, when you use a POCO for an entity you can opt-in to get behaviors such as "lazy-loading" and "change tracking" at runtime merely by ensuring that your type has the following characteristics: The class must be public and not sealed. The class must have a public or protected parameter-less constructor. The class must have public or protected properties Adhere to this and your type is magically endowed with these behaviors without any additional programming on your part. Behind the scenes the framework subclasses your type at runtime and creates a "dynamic proxy" which has these additional behaviors and when you navigate properties of your POCO, the framework replaces the POCO type with derived type instances. The MOQ framework does simlar magic. Let's say you have a simple interface:   public interface IFoo      {          int GetNum();      }   We can verify that the GetNum() was invoked on a mock like so:   var mock = new Mock<IFoo>(MockBehavior.Default);   mock.Setup(f => f.GetNum());   var num = mock.Object.GetNum();   mock.Verify(f => f.GetNum());   Beind the scenes the MOQ framework is generating a dynamic proxy by implementing IFoo at runtime. the call to moq.Object returns the dynamic proxy on which we then call "GetNum" and then verify that this method was invoked. No dark magic at all, just clever programming is what's going on here, just not visible and hence appears magical! Let's create a simple dynamic proxy generator which accepts an interface type and dynamically creates a proxy implementing the interface type specified at runtime.     public static class DynamicProxyGenerator   {       public static T GetInstanceFor<T>()       {           Type typeOfT = typeof(T);           var methodInfos = typeOfT.GetMethods();           AssemblyName assName = new AssemblyName("testAssembly");           var assBuilder = AppDomain.CurrentDomain.DefineDynamicAssembly(assName, AssemblyBuilderAccess.RunAndSave);           var moduleBuilder = assBuilder.DefineDynamicModule("testModule", "test.dll");           var typeBuilder = moduleBuilder.DefineType(typeOfT.Name + "Proxy", TypeAttributes.Public);              typeBuilder.AddInterfaceImplementation(typeOfT);           var ctorBuilder = typeBuilder.DefineConstructor(                     MethodAttributes.Public,                     CallingConventions.Standard,                     new Type[] { });           var ilGenerator = ctorBuilder.GetILGenerator();           ilGenerator.EmitWriteLine("Creating Proxy instance");           ilGenerator.Emit(OpCodes.Ret);           foreach (var methodInfo in methodInfos)           {               var methodBuilder = typeBuilder.DefineMethod(                   methodInfo.Name,                   MethodAttributes.Public | MethodAttributes.Virtual,                   methodInfo.ReturnType,                   methodInfo.GetParameters().Select(p => p.GetType()).ToArray()                   );               var methodILGen = methodBuilder.GetILGenerator();               methodILGen.EmitWriteLine("I'm a proxy");               if (methodInfo.ReturnType == typeof(void))               {                   methodILGen.Emit(OpCodes.Ret);               }               else               {                   if (methodInfo.ReturnType.IsValueType || methodInfo.ReturnType.IsEnum)                   {                       MethodInfo getMethod = typeof(Activator).GetMethod(/span>"CreateInstance",new Type[]{typeof((Type)});                                               LocalBuilder lb = methodILGen.DeclareLocal(methodInfo.ReturnType);                       methodILGen.Emit(OpCodes.Ldtoken, lb.LocalType);                       methodILGen.Emit(OpCodes.Call, typeofype).GetMethod("GetTypeFromHandle"));  ));                       methodILGen.Emit(OpCodes.Callvirt, getMethod);                       methodILGen.Emit(OpCodes.Unbox_Any, lb.LocalType);                                                              }                 else                   {                       methodILGen.Emit(OpCodes.Ldnull);                   }                   methodILGen.Emit(OpCodes.Ret);               }               typeBuilder.DefineMethodOverride(methodBuilder, methodInfo);           }                     Type constructedType = typeBuilder.CreateType();           var instance = Activator.CreateInstance(constructedType);           return (T)instance;       }   }   Dynamic proxies are created by calling into the following main types: AssemblyBuilder, TypeBuilder, Modulebuilder and ILGenerator. These types enable dynamically creating an assembly and emitting .NET modules and types in that assembly, all using IL instructions. Let's break down the code above a bit and examine it piece by piece                Type typeOfT = typeof(T);              var methodInfos = typeOfT.GetMethods();              AssemblyName assName = new AssemblyName("testAssembly");              var assBuilder = AppDomain.CurrentDomain.DefineDynamicAssembly(assName, AssemblyBuilderAccess.RunAndSave);              var moduleBuilder = assBuilder.DefineDynamicModule("testModule", "test.dll");              var typeBuilder = moduleBuilder.DefineType(typeOfT.Name + "Proxy", TypeAttributes.Public);   We are instructing the runtime to create an assembly caled "test.dll"and in this assembly we then emit a new module called "testModule". We then emit a new type definition of name "typeName"Proxy into this new module. This is the definition for the "dynamic proxy" for type T                 typeBuilder.AddInterfaceImplementation(typeOfT);               var ctorBuilder = typeBuilder.DefineConstructor(                         MethodAttributes.Public,                         CallingConventions.Standard,                         new Type[] { });               var ilGenerator = ctorBuilder.GetILGenerator();               ilGenerator.EmitWriteLine("Creating Proxy instance");               ilGenerator.Emit(OpCodes.Ret);   The newly created type implements type T and defines a default parameterless constructor in which we emit a call to Console.WriteLine. This call is not necessary but we do this so that we can see first hand that when the proxy is constructed, when our default constructor is invoked.   var methodBuilder = typeBuilder.DefineMethod(                      methodInfo.Name,                      MethodAttributes.Public | MethodAttributes.Virtual,                      methodInfo.ReturnType,                      methodInfo.GetParameters().Select(p => p.GetType()).ToArray()                      );   We then iterate over each method declared on type T and add a method definition of the same name into our "dynamic proxy" definition     if (methodInfo.ReturnType == typeof(void))   {       methodILGen.Emit(OpCodes.Ret);   }   If the return type specified in the method declaration of T is void we simply return.     if (methodInfo.ReturnType.IsValueType || methodInfo.ReturnType.IsEnum)   {                               MethodInfo getMethod = typeof(Activator).GetMethod("CreateInstance",                                                         new Type[]{typeof(Type)});                               LocalBuilder lb = methodILGen.DeclareLocal(methodInfo.ReturnType);                                                     methodILGen.Emit(OpCodes.Ldtoken, lb.LocalType);       methodILGen.Emit(OpCodes.Call, typeof(Type).GetMethod("GetTypeFromHandle"));       methodILGen.Emit(OpCodes.Callvirt, getMethod);       methodILGen.Emit(OpCodes.Unbox_Any, lb.LocalType);   }   If the return type in the method declaration of T is either a value type or an enum, then we need to create an instance of the value type and return that instance the caller. In order to accomplish that we need to do the following: 1) Get a handle to the Activator.CreateInstance method 2) Declare a local variable which represents the Type of the return type(i.e the type object of the return type) specified on the method declaration of T(obtained from the MethodInfo) and push this Type object onto the evaluation stack. In reality a RuntimeTypeHandle is what is pushed onto the stack. 3) Invoke the "GetTypeFromHandle" method(a static method in the Type class) passing in the RuntimeTypeHandle pushed onto the stack previously as an argument, the result of this invocation is a Type object (representing the method's return type) which is pushed onto the top of the evaluation stack. 4) Invoke Activator.CreateInstance passing in the Type object from step 3, the result of this invocation is an instance of the value type boxed as a reference type and pushed onto the top of the evaluation stack. 5) Unbox the result and place it into the local variable of the return type defined in step 2   methodILGen.Emit(OpCodes.Ldnull);   If the return type is a reference type then we just load a null onto the evaluation stack   methodILGen.Emit(OpCodes.Ret);   Emit a a return statement to return whatever is on top of the evaluation stack(null or an instance of a value type) back to the caller     Type constructedType = typeBuilder.CreateType();   var instance = Activator.CreateInstance(constructedType);   return (T)instance;   Now that we have a definition of the "dynamic proxy" implementing all the methods declared on T, we can now create an instance of the proxy type and return that out typed as T. The caller can now invoke the generator and request a dynamic proxy for any type T. In our example when the client invokes GetNum() we get back "0". Lets add a new method on the interface called DayOfWeek GetDay()   public interface IFoo      {          int GetNum();          DayOfWeek GetDay();      }   When GetDay() is invoked, the "dynamic proxy" returns "Sunday" since that is the default value for the DayOfWeek enum This is a very trivial example of dynammic proxies, frameworks like MOQ have a way more sophisticated implementation of this paradigm where in you can instruct the framework to create proxies which return specified values for a method implementation.

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