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  • macro function for printing

    - by seven
    Hi, if for example i have : define PRINT(x) fprintf(stderr, x); and in code i append it : PRINT(("print this")) output is : [print this] if i append it : PRINT(("print %s", "this")) output is : [this] could someone explain me why it receives just the "this" argument and not the whole string ?

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  • Function template overloading: link error

    - by matt
    I'm trying to overload a "display" method as follows: template <typename T> void imShow(T* img, int ImgW, int ImgH); template <typename T1, typename T2> void imShow(T1* img1, T2* img2, int ImgW, int ImgH); I am then calling the template with unsigned char* im1 and char* im2: imShow(im1, im2, ImgW, ImgH); This compiles fine, but i get a link error "unresolved external symbol" for: imShow<unsigned char,char>(unsigned char *,char *,int,int) I don't understand what I did wrong!

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  • Pass temporary object to function that takes pointer

    - by Happy Mittal
    I tried following code : #include<iostream> #include<string> using namespace std; string f1(string s) { return s="f1 called"; } void f2(string *s) { cout<<*s<<endl; } int main() { string str; f2(&f1(str)); } But this code doesn't compile. What I think is : f1 returns by value so it creates temporary, of which I am taking address and passing to f2. Now Please explain me where I am thinking wrong?

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  • Help with Oracle SQL Count function! =)

    - by user363024
    Hi guys.. The question im struggling with is this: i have a list of helicopter names in different charters and i need to find out WHICH helicopter has the least amount of charters booked. Once i find that out i need to ONLY display the one that has the least. I so far have this: SELECT Helicopter_Name COUNT (Distinct Charter_NUM) FROM Charter_Table GROUP BY Helicopter Name ^ this is where i am stuck, i realise MIN could be used to pick out the value that is the smallest but i am not sure how to integrate this into the command. Something like Where MIN = MIN Value Id really appreciate it

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  • [C++] My First Go With Function Templates

    - by bobber205
    Thought it was pretty straight forward. But I get a "iterator not dereferencable" errro when running the below code. What's wrong? template<typename T> struct SumsTo : public std::binary_function<T, T, bool> { int myInt; SumsTo(int a) { myInt = a; } bool operator()(const T& l, const T& r) { cout << l << " + " << r; if ((l + r) == myInt) { cout << " does add to " << myInt; } else { cout << " DOES NOT add to " << myInt; } return true; } }; void main() { list<int> l1; l1.push_back(1); l1.push_back(2); l1.push_back(3); l1.push_back(4); list<int> l2; l2.push_back(9); l2.push_back(8); l2.push_back(7); l2.push_back(6); transform(l1.begin(), l1.end(), l2.begin(), l2.end(), SumsTo<int>(10) ); }

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  • linq delegate function checking from objects

    - by Philip
    I am trying to find the list of objects which can be replaced. Class Letter{ int ID; string Name; string AdvCode; int isDeleted; } Class Replacers{ int ID; string MainAdvCode; string ReplacesAdvCode; } example data: Replacers 0 455 400 1 955 400 2 955 455 such that if a Letter has and Advcode of 455 and another has a code of 400 the 400 gets marked for deletion. And then if another Letter has a 955 then the 455 gets marked for deletion and the 400 (which is already marked) is marked for deletion. The problem is with my current code the 400 and 455 is marking itself for deletion?!?!? Public class Main{ List<Letter> Letters; List<Replacers> replaces; //select the ones to replace the replacements aka the little guys //check if the replacements replacer exists if yes mark deleted var filterMethodReplacements = new Func<Letter, bool>(IsAdvInReplacements);//Working var filterMethodReplacers = new Func<Letter, bool>(IsAdvInReplacers);//NOT WORKING???? var resReplacements=letters.Where(filterMethodReplacements);//working foreach (Letter letter in resReplacements) { //select the Replacers aka the ones that contain the little guys var resReplacers = letters.Where(filterMethodReplacers); if (resReplacers != null) letter.isDeleted = 1; } } } private bool IsAdvInReplacements(Letter letter) { return (from a in Replacables where a.ReplaceAdvCode == letter.AdvCode select a).Any(); } private bool IsAdvInReplacers(Letter letter) { //?????????????????????????????? return (from a in Replacables where a.MainAdvCode == letter.AdvCode select a).Any(); } }

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  • Multithreading A Function in VB.Net

    - by Ben
    I am trying to multi thread my application so as it is visible while it is executing the process, this is what I have so far: Private Sub SendPOST(ByVal URL As String) Try Dim DataBytes As Byte() = Encoding.ASCII.GetBytes("") Dim Request As HttpWebRequest = TryCast(WebRequest.Create(URL.Trim & "/webdav/"), HttpWebRequest) Request.Method = "POST" Request.ContentType = "application/x-www-form-urlencoded" Request.ContentLength = DataBytes.Length Request.Timeout = 1000 Request.ReadWriteTimeout = 1000 Dim PostData As Stream = Request.GetRequestStream() PostData.Write(DataBytes, 0, DataBytes.Length) Dim Response As WebResponse = Request.GetResponse() Dim ResponseStream As Stream = Response.GetResponseStream() Dim StreamReader As New IO.StreamReader(ResponseStream) Dim Text As String = StreamReader.ReadToEnd() PostData.Close() Catch ex As Exception If ex.ToString.Contains("401") Then TextBox2.Text = TextBox2.Text & URL & "/webdav/" & vbNewLine End If End Try End Sub Public Sub G0() Dim siteSplit() As String = TextBox1.Text.Split(vbNewLine) For i = 0 To siteSplit.Count - 1 Try If siteSplit(i).Contains("http://") Then SendPOST(siteSplit(i).Trim) Else SendPOST("http://" & siteSplit(i).Trim) End If Catch ex As Exception End Try Next End Sub Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load Dim t As Thread t = New Thread(AddressOf Me.G0) t.Start() End Sub However, the 'G0' sub code is not being executed at all, and I need to multi thread the 'SendPOST' as that is what slows the application.

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  • c++ function overloading, making fwrite/fread act like PHP versions

    - by Newbie
    I'm used to the PHP fwrite/fread parameter orders, and i want to make them the same in C++ too. I want it to work with char and string types, and also any data type i put in it (only if length is defined). I am total noob on c++, this is what i made so far: size_t fwrite(FILE *fp, const std::string buf, const size_t len = SIZE_MAX){ if(len == SIZE_MAX){ return fwrite(buf.c_str(), 1, buf.length(), fp); }else{ return fwrite(buf.c_str(), 1, len, fp); } } size_t fwrite(FILE *fp, const void *buf, const size_t len = SIZE_MAX){ if(len == SIZE_MAX){ return fwrite((const char *)buf, 1, strlen((const char *)buf), fp); }else{ return fwrite(buf, 1, len, fp); } } Should this work just fine? And how should this be done if i wanted to do it the absolutely best possible way?

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  • Assigning function within function object without invoking the function itself.

    - by webzide
    Dear experts, I am trying to assign an function within an function object property without actually invoking then function itself. for instance, I have the following function object class definition function objectOne(name, value, id){ this.name=name; this.value=value; this.id=id; this.methodOne=methodFunction(this); } the last line this.methodOne=methodFunction(this); I want to pass the current object to the function but at the same time i don't want to execute the function right now. But if I do it this way without the bracket this.methodOne=methodFunction then the argument of this object would not be passed as a parameter to the function. Is there a way to work through this. Thank you in advance

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  • Xpath help function

    - by NA
    Hi i have a document from which i am trying to extract a date. But the problem is within the node along with the date their is some text too. Something like <div class="postHeader"> Posted on July 20, 2009 9:22 PM PDT </div> From this tag i just want the date item not the Posted on text. something like ./xhtml:div[@class = 'postHeader'] is getting everything. and to be precise, the document i have is basically a nodelist of this elements for eg i will get 10 nodes of these elements with different date values but to be worse the problem is sometime inside these tags some random other tags also pops us like anchors etc. Can i write a universal expath which will just get the date out of the div tag?

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  • How can I pass a const array or a variable array to a function in C?

    - by CSharperWithJava
    I have a simple function Bar that uses a set of values from a data set that is passed in in the form of an Array of data structures. The data can come from two sources: a constant initialized array of default values, or a dynamically updated cache. The calling function determines which data is used and should be passed to Bar. Bar doesn't need to edit any of the data and in fact should never do so. How should I declare Bar's data parameter so that I can provide data from either set? union Foo { long _long; int _int; } static const Foo DEFAULTS[8] = {1,10,100,1000,10000,100000,1000000,10000000}; static Foo Cache[8] = {0}; void Bar(Foo* dataSet, int len);//example function prototype Note, this is C, NOT C++ if that makes a difference; Edit Oh, one more thing. When I use the example prototype I get a type qualifier mismatch warning, (because I'm passing a mutable reference to a const array?). What do I have to change for that?

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  • Better variant of getting the output dinamically-allocated array from the function?

    - by Raigomaru
    Here is to variants. First: int n = 42; int* some_function(int* input) { int* result = new int[n]; // some code return result; } void main() { int* input = new int[n]; int* output = some_function(input); delete[] input; delete[] output; } Here the function returns the memory, allocated inside the function. Second variant: int n = 42; void some_function(int* input, int* output) { // some code } void main() { int* input = new int[n]; int* output = new int[n]; some_function(input, output); delete[] input; delete[] output; } Here the memory is allocated outside the function. Now I use the first variant. But I now that many built-in c++ functions use the second variant. The first variant is more comfortable (in my opinion). But the second one also has some advantages (you allocate and delete memory in the same block). Maybe it's a silly question but what variant is better and why?

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  • C# Function Inheritance--Use Child Class Vars with Base Class Function

    - by Sean O'Connor
    Good day, I have a fairly simple question to experienced C# programmers. Basically, I would like to have an abstract base class that contains a function that relies on the values of child classes. I have tried code similar to the following, but the compiler complains that SomeVariable is null when SomeFunction() attempts to use it. Base class: public abstract class BaseClass { protected virtual SomeType SomeVariable; public BaseClass() { this.SomeFunction(); } protected void SomeFunction() { //DO SOMETHING WITH SomeVariable } } A child class: public class ChildClass:BaseClass { protected override SomeType SomeVariable=SomeValue; } Now I would expect that when I do: ChildClass CC=new ChildClass(); A new instance of ChildClass should be made and CC would run its inherited SomeFunction using SomeValue. However, this is not what happens. The compiler complains that SomeVariable is null in BaseClass. Is what I want to do even possible in C#? I have used other managed languages that allow me to do such things, so I certain I am just making a simple mistake here. Any help is greatly appreciated, thank you.

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  • How do I create a partial function with generics in scala?

    - by Matteo Caprari
    Hello. I'm trying to write a performance measurements library for Scala. My idea is to transparently 'mark' sections so that the execution time can be collected. Unfortunately I wasn't able to bend the compiler to my will. An admittedly contrived example of what I have in mind: // generate a timing function val myTimer = mkTimer('myTimer) // see how the timing function returns the right type depending on the // type of the function it is passed to it val act = actor { loop { receive { case 'Int => val calc = myTimer { (1 to 100000).sum } val result = calc + 10 // calc must be Int self reply (result) case 'String => val calc = myTimer { (1 to 100000).mkString } val result = calc + " String" // calc must be String self reply (result) } Now, this is the farthest I got: trait Timing { def time[T <: Any](name: Symbol)(op: => T) :T = { val start = System.nanoTime val result = op val elapsed = System.nanoTime - start println(name + ": " + elapsed) result } def mkTimer[T <: Any](name: Symbol) : (() => T) => () => T = { type c = () => T time(name)(_ : c) } } Using the time function directly works and the compiler correctly uses the return type of the anonymous function to type the 'time' function: val bigString = time('timerBigString) { (1 to 100000).mkString("-") } println (bigString) Great as it seems, this pattern has a number of shortcomings: forces the user to reuse the same symbol at each invocation makes it more difficult to do more advanced stuff like predefined project-level timers does not allow the library to initialize once a data structure for 'timerBigString So here it comes mkTimer, that would allow me to partially apply the time function and reuse it. I use mkTimer like this: val myTimer = mkTimer('aTimer) val myString= myTimer { (1 to 100000).mkString("-") } println (myString) But I get a compiler error: error: type mismatch; found : String required: () => Nothing (1 to 100000).mkString("-") I get the same error if I inline the currying: val timerBigString = time('timerBigString) _ val bigString = timerBigString { (1 to 100000).mkString("-") } println (bigString) This works if I do val timerBigString = time('timerBigString) (_: String), but this is not what I want. I'd like to defer typing of the partially applied function until application. I conclude that the compiler is deciding the return type of the partial function when I first create it, chosing "Nothing" because it can't make a better informed choice. So I guess what I'm looking for is a sort of late-binding of the partially applied function. Is there any way to do this? Or maybe is there a completely different path I could follow? Well, thanks for reading this far -teo

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  • How to call a prototyped function from within the prototyped "class"?

    - by Jorge
    function FakeClass(){}; FakeClass.prototype.someMethod = function(){}; FakeClass.prototype.otherMethod = function(){ //need to call someMethod() here. } I need to call someMethod from otherMethod, but apparently it doesn't work. If i build it as a single function (not prototyped), i can call it, but calling a prototyped does not work. How can i do it as if i was treating the function just like a class method?

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  • Function inside .profile results in no log-in

    - by bioShark
    I've created a custom function in my .profile, and I've added right at the bottom, after my custom aliases : # custom functions function eclipse-gtk { cd ~/development/eclipse-juno ./eclipse_wb.sh & cd - } The function starts a custom version of my eclipse. After I've added it, because I didn't wanted to log-out/log-in, I've reloaded my profile with the command: . ~/.profile and then I've tested my function by calling eclipse-gtk and it worked without any issue. Today when I booted, I couldn't log in. After providing my password, in a few seconds I was back at the log-in screen. Dropping to command line using CTR + ALT + F1, I've commented out the function in my .profile and the log-in was possible without any issue. My question is, what did I do wrong when I wrote the function? And if there is something wrong, why did it work yesterday after reloading the profile. Thanks in advance. Using: Ubuntu 12.04

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  • How to get SQL Function run a different query and return value from either query?

    - by RoguePlanetoid
    I need a function, but cannot seem to get it quite right, I have looked at examples here and elsewhere and cannot seem to get this just right, I need an optional item to be included in my query, I have this query (which works): SELECT TOP 100 PERCENT SKU, Description, LEN(CONVERT(VARCHAR (1000),Description)) AS LenDesc FROM tblItem WHERE Title = @Title AND Manufacturer = @Manufacturer ORDER BY LenDesc DESC This works within a Function, however the Manufacturer is Optional for this search - which is to find the description of a similar item, if none is present, the other query is: SELECT TOP 100 PERCENT SKU, Description, LEN(CONVERT(VARCHAR (1000),Description)) AS LenDesc FROM tblItem WHERE Title = @Title ORDER BY LenDesc DESC Which is missing the Manufacturer, how to I get my function to use either query based on the Manufacturer Value being present or not. The reason is I will have a function which first checks an SKU for a Description, if it is not present - it uses this method to get a Description from a Similar Product, then updates the product being added with the similar product's description. Here is the function so far: ALTER FUNCTION [dbo].[GetDescriptionByTitleManufacturer] ( @Title varchar(400), @Manufacturer varchar(160) ) RETURNS TABLE AS RETURN ( SELECT TOP 100 PERCENT SKU, Description, LEN(CONVERT(VARCHAR (1000),Description)) AS LenDesc FROM tblItem WHERE Title = @Title AND Manufacturer = @Manufacturer ORDER BY LenDesc DESC ) I've tried adding BEGINs and IF...ELSEs but get errors or syntax problems each way I try it, I want to be able to do something like this pseudo-function (which does not work): ALTER FUNCTION [dbo].[GetDescriptionByTitleManufacturer] ( @Title varchar(400), @Manufacturer varchar(160) ) RETURNS TABLE AS BEGIN IF (@Manufacturer = Null) RETURN ( SELECT TOP 100 PERCENT SKU, Description, LEN(CONVERT(VARCHAR (1000),Description)) AS LenDesc FROM tblItem WHERE Title = @Title ORDER BY LenDesc DESC ) ELSE RETURN ( SELECT TOP 100 PERCENT SKU, Description, LEN(CONVERT(VARCHAR (1000),Description)) AS LenDesc FROM tblItem WHERE Title = @Title AND Manufacturer = @Manufacturer ORDER BY LenDesc DESC ) END

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