Search Results

Search found 1552 results on 63 pages for 'homework'.

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

Page 31/63 | < Previous Page | 27 28 29 30 31 32 33 34 35 36 37 38  | Next Page >

  • Using sigprocmask to implement locks

    - by EpsilonVector
    I'm implementing user threads in Linux kernel 2.4, and I'm using ualarm to invoke context switches between the threads. We have a requirement that our thread library's functions should be uninterruptable, so I looked into blocking signals and learned that using sigprocmask is the standard way to do this. However, it looks like I need to do quite a lot to implement this: sigset_t new_set, old_set; sigemptyset(&new_set); sigaddset(&new_set, SIGALRM); sigprocmask(SIG_BLOCK, &new_set, &old_set); This blocks SIGALARM but it does this with 3 function invocations! A lot can happen in the time it takes for these functions to run, including the signal being sent. The best idea I had to mitigate this was temporarily disabling ualarm, like this: sigset_t new_set, old_set; time=ualarm(0,0); sigemptyset(&new_set); sigaddset(&new_set, SIGALRM); sigprocmask(SIG_BLOCK, &new_set, &old_set); ualarm(time, 0); Which is fine except that this feels verbose. Isn't there a better way to do this?

    Read the article

  • Find the highest number of occurences in a column in SQL

    - by Ronnie
    Given this table: Order custName description to_char(price) A desa $14 B desb $14 C desc $21 D desd $65 E dese $21 F desf $78 G desg $14 H desh $21 I am trying to display the whole row where prices have the highest occurances, in this case $14 and $21 I believe there needs to be a subquery. So i started out with this: select max(count(price)) from orders group by price which gives me 3. after some time i didn't think that was helpful. i believe i needed the value 14 and 21 rather the the count so i can put that in the where clause. but I'm stuck how to display that. any help?

    Read the article

  • Java - Removing duplicates in an ArrayList

    - by Will
    I'm working on a program that uses an ArrayList to store Strings. The program prompts the user with a menu and allows the user to choose an operation to perform. Such operations are adding Strings to the List, printing the entries etc. What I want to be able to do is create a method called removeDuplicates().This method will search the ArrayList and remove any duplicated values. I want to leave one instance of the duplicated value(s) within the list. I also want this method to return the total number of duplicates removed. I've been trying to use nested loops to accomplish this but I've been running into trouble because when entries get deleted, the indexing of the ArrayList gets altered and things don't work as they should. I know conceptually what I need to do but I'm having trouble implementing this idea in code. Here is some pseudo code: start with first entry; check each subsequent entry in the list and see if it matches the first entry; remove each subsequent entry in the list that matches the first entry; after all entries have been examined, move on to the second entry; check each entry in the list and see if it matches the second entry; remove each entry in the list that matches the second entry; repeat for entry in the list Here's the code I have so far: public int removeDuplicates() { int duplicates = 0; for ( int i = 0; i < strings.size(); i++ ) { for ( int j = 0; j < strings.size(); j++ ) { if ( i == j ) { // i & j refer to same entry so do nothing } else if ( strings.get( j ).equals( strings.get( i ) ) ) { strings.remove( j ); duplicates++; } } } return duplicates; }

    Read the article

  • display multiple errors via bool flag c++

    - by igor
    Been a long night, but stuck on this and now am getting "segmentation fault" in my compiler.. Basically I'm trying to display all the errors (the cout) needed. If there is more than one error, I am to display all of them. bool validMove(const Square board[BOARD_SIZE][BOARD_SIZE], int x, int y, int value) { int index; bool moveError = true; const int row_conflict(0), column_conflict(1), grid_conflict(2); int v_subgrid=x/3; int h_subgrid=y/3; getCoords(x,y); for(index=0;index<9;index++) if(board[x][index].number==value){ cout<<"That value is in conflict in this row\n"; moveError=false; } for(index=0;index<9;index++) if(board[index][y].number==value){ cout<<"That value is in conflict in this column\n"; moveError=false; } for(int i=v_subgrid*3;i<(v_subgrid*3 +3);i++){ for(int j=h_subgrid*3;j<(h_subgrid*3+3);j++){ if(board[i][j].number==value){ cout<<"That value is in conflict in this subgrid\n"; moveError=false; } } } return true; }

    Read the article

  • How can I combine result and subquery for IN comparison (mysql)

    - by user325804
    In order for a school project i need to create the following situation within one mysql query. The situation is as such, that a child's tags and a parent's tags need to be combined into one, and compared to a site's tags, depending on a few extra simple equals to lines. For this to happen I only see the option that the result of a subquery is combined with a sub query within that query, as such: SELECT tag.*, (SELECT group_concat(t1.id, ',', (SELECT group_concat(tag.id) FROM adcampaign INNER JOIN adcampaign_tag ON adcampaign.id = adcampaign_tag.adcampaign_id INNER JOIN tag ON adcampaign_tag.tag_id = tag.id WHERE adcampaign.id = 1)) FROM ad, ad_tag, tag AS t1 WHERE ad.id = ad_tag.ad_id AND ad_tag.tag_id = t1.id AND ad.adcampaign_id = 1 AND ad.agecategory_id = 1 AND ad.adsize_id = 1 AND ad.adtype_id = 1) as tags FROM tag WHERE tag.id IN tags But the IN comparison only returns the first result because now the tags aren't a list but a concanated string. Anyone got any suggestion on this? I really need a way to combine it into one array

    Read the article

  • How to solve this problem with lists?

    - by osabri
    what i don't understand in my task here what kind of list i can use, and if it should have 2 attributes key and value ? or only value? with pointers to another node ofc the task: "design a function which create a list using input from the keyboard _ the prefered solution. Assume that some magic stops the input; so the length of a list is not known in advance.(alternative solution: a function which creates explicitly a fixed list. However, all other function can not assume any knowledge about the length of lists). Necessary utilities( additional functions to be created): a function which deallocates the memory used for lists and a function which prints the content of the list. let the element of lists contain a letter. Design a function which create a copy of such list. can't also understand the list line !!!!!???

    Read the article

  • Modelling in Agile Development

    - by bertzzie
    I'm writing a bachelor dissertation report where I'm developing a system with Agile methodology. Given that the development is an one man show, of course the "Agile" I did was not really agile at all (from my understanding at least). So I want some perspective from SO crowds, who is of course a professional, real world, developer with tons of experience. I think real world experience is better than the theory and experiments that I did. My question is: Do we model during development time when using Agile? UML? DFD? Or a Functional Specification is enough1? If modelling is not really necessary, what do we use to communicate to the user, as the user almost always won't understand UML or DFD? For my system, I use UI & UX Design with heavy prototyping, but then I don't have time to draw UML any more. Which one is better? 1 http://www.joelonsoftware.com/articles/fog0000000036.html I hope the question's not "subjective and argumentative" as I know this question exist because of my lack of understanding in the agile development. If it is, could someone just give me a pointer or reference about that? Possible duplicate: Do you use UML in Agile development practices?

    Read the article

  • How can I correctly calculate the direction for a moving object?

    - by Jakub Hampl
    I'm solving the following problem: I have an object and I know its position now and its position 300ms ago. I assume the object is moving. I have a point to which I want the object to get. What I need is to get the angle from my current object to the destination point in such a format that I know whether to turn left or right. The idea is to assume the current angle from the last known position and the current position. I'm trying to solve this in MATLAB. I've tried using several variations with atan2 but either I get the wrong angle in some situations (like when my object is going in circles) or I get the wrong angle in all situations. Examples of code that screws up: a = new - old; b = dest - new; alpha = atan2(a(2) - b(2), a(1) - b(1); where new is the current position (eg. x = 40; y = 60; new = [x y];), old is the 300ms old position and dest is the destination point. Edit Here's a picture to demonstrate the problem with a few examples: In the above image there are a few points plotted and annotated. The black line indicates our estimated current facing of the object. If the destination point is dest1 I would expect an angle of about 88°. If the destination point is dest2 I would expect an angle of about 110°. If the destination point is dest3 I would expect an angle of about -80°.

    Read the article

  • Strange problem with simple multithreading program in Java

    - by Elizabeth
    Hello, I am just starting play with multithreading programming. I would like to my program show alternately character '-' and '+' but it doesn't. My task is to use synchronized keyword. As far I have: class FunnyStringGenerator{ private char c; public FunnyStringGenerator(){ c = '-'; } public synchronized char next(){ if(c == '-'){ c = '+'; } else{ c = '-'; } return c; } } class ThreadToGenerateStr implements Runnable{ FunnyStringGenerator gen; public ThreadToGenerateStr(FunnyStringGenerator fsg){ gen = fsg; } @Override public void run() { for(int i = 0; i < 10; i++){ System.out.print(gen.next()); } } } public class Main{ public static void main(String[] args) throws IOException { FunnyStringGenerator FSG = new FunnyStringGenerator(); ExecutorService exec = Executors.newCachedThreadPool(); for(int i = 0; i < 20; i++){ exec.execute(new ThreadToGenerateStr(FSG)); } } } EDIT: I also testing Thread.sleep in run method instead for loop.

    Read the article

  • Why is my panel not positioned correctly even after setting the boundaries?

    - by nutellafella
    I'm trying to make a simple GUI with radio buttons and I grouped them into one panel. I wanted it positioned on the leftmost side so I used the setBounds method. Whatever numbers I put on the parameters, the panel won't move. Are panels not affected by the setBounds method? Or is there another way to position my panel. Here's the snippet of my code: JPanel radioPanel = new JPanel(); radioPanel.setLayout(new GridLayout(3,1)); JRadioButton Rbutton1 = new JRadioButton("Credit Card"); JRadioButton Rbutton2 = new JRadioButton("E-Funds"); JRadioButton Rbutton3 = new JRadioButton("Check"); Rbutton3.setSelected(true); ButtonGroup Bgroup = new ButtonGroup(); Bgroup.add(Rbutton1); Bgroup.add(Rbutton2); Bgroup.add(Rbutton3); radioPanel.add(Rbutton1); radioPanel.add(Rbutton2); radioPanel.add(Rbutton3); radioPanel.setBounds(10,50,50,40); //this is where I'm trying to position the panel with the radio buttons paymentPanel.add(radioPanel); contentPane.add(paymentPanel); //contentPane is the frame contentPane.setVisible(true);

    Read the article

  • Unresolved external symbol error in c++

    - by Crystal
    I am trying to do a simple hw problem involving namespace, static data members and functions. I am getting an unresolved external symbol error Error 1 error LNK2001: unresolved external symbol "private: static double JWong::SavingsAccount::annualInterestRate" (?annualInterestRate@SavingsAccount@JWong@@0NA) SavingsAccount.obj SavingsAccount And I don't see why I am getting this error. Maybe I don't know something about static variables compared to regular data members that is causing this error. Here is my code: SavingsAccount.h file #ifndef JWONG_SAVINGSACCOUNT_H #define JWONG_SAVINGSACCOUNT_H namespace JWong { class SavingsAccount { public: // default constructor SavingsAccount(); // constructor SavingsAccount(double savingsBalance); double getSavingsBalance(); void setSavingsBalance(double savingsBalance); double calculateMonthlyInterest(); // static functions static void modifyInterestRate(double newInterestRate); static double getAnnualInterestRest(); private: double savingsBalance; // static members static double annualInterestRate; }; } #endif SavingsAccount.cpp file #include <iostream> #include "SavingsAccount.h" // default constructor, set savingsBalance to 0 JWong::SavingsAccount::SavingsAccount() : savingsBalance(0) {} // constructor JWong::SavingsAccount::SavingsAccount(double savingsBalance) : savingsBalance(savingsBalance) {} double JWong::SavingsAccount::getSavingsBalance() { return savingsBalance; } void JWong::SavingsAccount::setSavingsBalance(double savingsBalance) { this->savingsBalance = savingsBalance; } // returns monthly interest and sets savingsBalance to new amount double JWong::SavingsAccount::calculateMonthlyInterest() { double monthlyInterest = savingsBalance * SavingsAccount::annualInterestRate / 12; setSavingsBalance(savingsBalance + monthlyInterest); return monthlyInterest; } void JWong::SavingsAccount::modifyInterestRate(double newInterestRate) { SavingsAccount::annualInterestRate = newInterestRate; } double JWong::SavingsAccount::getAnnualInterestRest() { return SavingsAccount::annualInterestRate; }

    Read the article

  • How to convert between different currencies?

    - by sil3nt
    Hey there, this is part of a question i got in class, im at the final stretch but this has become a major problem. In it im given a certain value which is called the "gold value" and it is 40.5, this value changes in input. and i have these constants const int RUBIES_PER_DIAMOND = 5; // relative values. * const int EMERALDS_PER_RUBY = 2; const int GOLDS_PER_EMERALDS = 5; const int SILVERS_PER_GOLD = 4; const int COPPERS_PER_SILVER = 5; const int DIAMOND_VALUE = 50; // gold values. * const int RUBY_VALUE = 10; const int EMERALD_VALUE = 5; const float SILVER_VALUE = 0.25; const float COPPER_VALUE = 0.05; which means that basically for every diamond there are 5 rubies, and for every ruby there are 2 emeralds. So on and so forth. and the "gold value" for every diamond for example is 50 (diamond value = 50) this is how much one diamond is worth in golds. my problem is converting 40.5 into these diamonds and ruby values. I know the answer is 4rubies and 2silvers but how do i write the algorithm for this so that it gives the best estimate for every goldvalue that comes along?? please help!, im at my wits end

    Read the article

  • help in security assignment

    - by scatman
    i have to write a program that sniffs network packets (part1-the simple part). and i have to update the program (part2) so that it will be able to terminate connections. the specific requirements are: construct raw packets by specifying data link layer and network layer information including appropriate source and destination MAC and IP addresses. These packets are intended to terminate the connection. To do so, you should used SOCK_RAW as the socket type to be able to set the header information by yourself. can anybody give me some ideas on the second part? should i hijack the session,apply a dos attack on one of the users?? all i need is some tips of how to terminate the connection. i am using c programming language. and this is a course assignment for the security course.

    Read the article

  • [java] Returning the element number of the longest string in an array

    - by JohnRoberts
    Hoookay, so. I'm trying to get the longestS method to take the user-inputted array of strings, then return the element number of the longest string in that array. I got it to the point where I was able to return the number of chars in the longest string, but I don't believe that will work for what I need. My problem is that I keep getting incompatible type errors when trying to figure this out. I don't understand the whole data type thing with strings yet. It's confusing me how I go about return a number of the array yet the array is of strings. The main method is fine, I got stuck on the ???? part. { public static void main(String [] args) { Scanner inp = new Scanner( System.in ); String [] responseArr= new String[4]; for (int i=0; i<4; i++) { System.out.println("Enter string "+(i+1)); responseArr[i] = inp.nextLine(); } int highest=longestS(responseArr); } public static int longestS(String[] values) { int largest=0 for( int i = 1; i < values.length; i++ ) { if ( ????? ) } return largest; } }

    Read the article

  • How to create and display a list in Java?

    - by lox
    i have to create a list of ,let's say 50 people, (in Java) and display the list, and i don't really know how to do that. so this is what i have tried to do so far . please correct and complete some of my code . public class Person { String name; String stuff; } public class CreatePerson { public static void ang() { ArrayList<Person> thing=new ArrayList<Person>(); Scanner diskScanner = new Scanner(in); for(int i=0; i<50; i++){ Person pers = new Person(); out.print("name: "); pers.name=diskScanner.nextLine(); out.print("stuff: "); pers.stuff=diskScanner.nextLine(); thing.add(pers); break; } // Display people for (int i=0; i<50; i++) { out.println(??);{ } } }}

    Read the article

  • Where can I find the transaction protocol used by Automated Teller Machines?

    - by Dave
    I'm doing a grad-school software engineering project and I'm looking for the protocol that governs communications between ATMs and bank networks. I've been googling for quite a while now, and though I'm finding all sorts of interesting information about ATMs, I'm surprised to find that there seems to be no industry standard for high-level communications. I'm not talking about 3DES or low-level transmission protocols, but something along the lines of an Interface Control Document; something that governs the sequence of events for various transactions: verify credentials, withdrawal, check balance, etc. Any ideas? Does anything like this even exist? I can't believe that after all this time the banks and ATM manufacturers are still just making this up as they go. A shorter question: if I wanted to go into the ATM software manufacturing business, where would I start looking for standards?

    Read the article

  • urgent..haskell mini interpreter

    - by mohamed elshikh
    i'm asked to implement this project and i have problems in part b which is the eval function this is the full describtion of the project You are required to implement an interpreter for mini-Haskell language. An interpreter is dened in Wikipedia as a computer program that executes, i.e. performs, instructions written in a programming language. The interpreter should be able to evaluate functions written in a special notation, which you will dene. A function is dened by: Function name Input Parameters : dened as a list of variables. The body of the function. The body of the function can be any of the following statements: a) Variable: The function may return any of the input variables. b) Arithmetic Expressions: The arithmetic expressions include input variables and addition, sub- traction, multiplication, division and modulus operations on arithmetic expressions. c) Boolean Expressions: The Boolean expressions include the ordering of arithmetic expressions (applying the relationships: <, =<, , = or =) and the anding, oring and negation of Boolean expressions. d) If-then-else statements: where the if keyword is followed by a Boolean expression. The then and else parts may be followed by any of the statements described here. e) Guarded expressions: where each case consists of a boolean expression and any of the statements described here. The expression consists of any number of cases. The rst case whose condition is true, its body should be evaluated. The guarded expression has to terminate with an otherwise case. f) Function calls: the body of the function may have a call to another function. Note that all inputs passed to the function will be of type Int. The output of the function can be of type Int or Bool. To implement the interpreter, you are required to implement the following: a) Dene a datatype for the following expressions: Variables Arithmetic expressions Boolean expressions If-then-else statements Guarded expressions Functions b) Implement the function eval which evaluates a function. It takes 3 inputs: The name of a function to be evaluated represented as a string. A list of inputs to that function. The arguments will always be of datatype Int. A list of functions. Each function is represented as instance of the datatype that you have created for functions. c) Implement the function get_type that returns the type of the function (as a string). The input to this function is the same as in part b. here is what i've done data Variable = v(char) data Arth= va Variable | Add Arth Arth | Sub Arth Arth | Times Arth Arth | Divide Arth Arth data Bol= Great Arth Arth | Small Arth Arth | Geq Arth Arth | Seq Arth Arth | And Bol Bol | Or Bol Bol | Neg Bol data Cond = data Guard = data Fun =cons String [Variable] Body data Body= bodycons(String) |Bol |Cond |Guard |Arth

    Read the article

  • consts and other animals

    - by bks
    Hello i have a cpp code wich i'm having trouble reading. a class B is defined now, i understand the first two lines, but the rest isn't clear enough. is the line "B const * pa2 = pa1" defines a const variable of type class B? if so, what does the next line do? B a2(2); B *pa1 = new B(a2); B const * pa2 = pa1; B const * const pa3 = pa2; also, i'm having trouble figuring out the difference between these two: char const *cst = “abc”; const int ci = 15; thank you

    Read the article

  • Java: How to check the random letters from a-z, out of 10 letters minimum 2 letter should be a vowel

    - by kalandar
    I am writing a program to validate the following scenarios: Scenario 1: I am using the Random class from java.util. The random class will generate 10 letters from a-z and within 10 letter, minimum 2 letters must be a vowels. Scenario 2: When the player 1 and player 2 form a word from A-Z, he will score some points. There will be a score for each letter. I have already assigned the values for A-Z. At the end of the game, the system should display a scores for player 1 and player 2. How do i do it? Please help. I will post my code here. Thanks a lot. =========================================== import java.util.Random; import java.util.Scanner; public class FindYourWords { public static void main(String[] args) { Random rand = new Random(); Scanner userInput = new Scanner(System.in); //==================Player object=============================================== Player playerOne = new Player(); playerOne.wordScore = 0; playerOne.choice = "blah"; playerOne.turn = true; Player playerTwo = new Player(); playerTwo.wordScore = 0; playerTwo.choice = "blah"; playerTwo.turn = false; //================== Alphabet ================================================== String[] newChars = { "a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z" }; //values of the 26 alphabets to be used int [] letterScore = {1,3,3,2,1,4,2,4,1,8,5,1,3,1,1,3,10,1,1,1,1,4,4,8,4,10}; // to assign score to the player1 and player 2 String[] vowel = { "a", "e", "i", "o", "u" }; // values for vowels int vow=0; System.out.println("FINDYOURWORDS\n"); int[] arrayRandom = new int[10]; //int array for word limiter String[] randomLetter = new String[10]; //storing the letters in newChars into this array //=============================================================================== boolean cont = true; while (cont) { if (playerOne.turn) { System.out.print("Letters of Player 1: "); } else if (!playerOne.turn) { System.out.print("Letters of Player 2: "); } for (int i = 0; i < arrayRandom.length; i++) { //running through the array limiter int r = rand.nextInt(newChars.length); //assigning random nums to the array of letters randomLetter[i] = newChars[r]; System.out.print(randomLetter[i]+ " "); } //input section for player System.out.println(""); System.out.println("Enter your word (or '@' to pass or '!' to quit): "); if (playerOne.turn) { playerOne.choice = userInput.next(); System.out.println(playerOne.turn); playerOne.turn = false; } else if (!playerOne.turn){ playerTwo.choice = userInput.next(); System.out.println(playerOne.turn); playerOne.turn = true; } //System.out.println(choice); String[] wordList = FileUtil.readDictFromFile("words.txt"); //Still dunno what this is for if (playerOne.choice.equals("@")) { playerOne.turn = false; } else if (playerTwo.choice.equals("@")) { playerOne.turn = true; } else if (playerOne.choice.equals("!")) { cont = false; } for (int i = 0; i < wordList.length; i++) { //System.out.println(wordList[i]); if (playerOne.choice.equalsIgnoreCase(wordList[i]) || playerTwo.choice.equalsIgnoreCase(wordList[i])){ } } } }}

    Read the article

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

< Previous Page | 27 28 29 30 31 32 33 34 35 36 37 38  | Next Page >