c++

(Solved) Taking Screen shot continuously without slow down the PC – C#

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You won’t find a basic answer here. They use much more involved mechanisms for detecting changes on the screen and sending them. Check out how terminal svcs work – http://technet.microsoft.com/en-us/library/cc755399%28WS.10%29.aspx ideally you are hooking into the GUI and monitoring events, etc. much more advanced than simply screen scraping. If you want to look at less … Read more

(Solved) How to extract numeric values from string?

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You could use regular expression to do this. Although this pattern is very naively implemented, it is a start. I’ve used Tuple instead of Vector, but you can easily change that yourself. static readonly Regex VectorRegex = new Regex(@”a:(?<A>[0-9]+\.[0-9]+);b:(?<B>[0-9]+\.[0-9]+);c:(?<C>[0-9]+\.[0-9]+)”, RegexOptions.Compiled); static Tuple<double, double, double> ParseVector(string input) { var m = VectorRegex.Match(input); if (m.Success) { double … Read more

(Solved) Why can templates only be implemented in the header file?

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Caveat: It is not necessary to put the implementation in the header file, see the alternative solution at the end of this answer. Anyway, the reason your code is failing is that, when instantiating a template, the compiler creates a new class with the given template argument. For example: template<typename T> struct Foo { T … Read more

(Solved) Why is “using namespace std;” considered bad practice?

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Introduction Using the “using namespace std;” statement in C++ is a controversial topic among developers. While it can be a convenient way to access the standard library, it can also lead to confusion and errors. In this article, we will discuss why using namespace std; is considered bad practice and what alternatives are available. We … Read more

(Solved) Do I cast the result of malloc?

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TL;DR int *sieve = (int *) malloc(sizeof(int) * length); has two problems. The cast and that you’re using the type instead of variable as argument for sizeof. Instead, do like this: int *sieve = malloc(sizeof *sieve * length); Long version No; you don’t cast the result, since: It is unnecessary, as void * is automatically … Read more

(Solved) What is an undefined reference/unresolved external symbol error and how do I fix it?

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Compiling a C++ program takes place in several steps, as specified by 2.2 (credits to Keith Thompson for the reference): The precedence among the syntax rules of translation is specified by the following phases [see footnote]. Physical source file characters are mapped, in an implementation-defined manner, to the basic source character set (introducing new-line characters … Read more