Questions tagged [c++]
C++ is a general-purpose programming language. Use this tag for questions about/utilizing C++. Do not also tag questions with [c] unless you have a good reason. C and C++ are different languages. Use a versioned tag such as [c++11], [c++20] etc. for questions specific to a standard revision.
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The Definitive C++ Book Guide and List
This question attempts to collect the few pearls among the dozens of bad C++ books that are published every year.
Unlike many other programming languages, which are often picked up on the go from ...
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What is an undefined reference/unresolved external symbol error and how do I fix it?
What are undefined reference/unresolved external symbol errors? What are common causes, and how do I fix and prevent these errors?
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What's the problem with "using namespace std;"?
I have heard using namespace std; is wrong, and that I should use std::cout and std::cin directly instead.
Why is this? Does it risk declaring variables that share the same name as something in the ...
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Why can templates only be implemented in the header file?
Quote from The C++ standard library: a tutorial and handbook:
The only portable way of using templates at the moment is to implement them in header files by using inline functions.
Why is this?
(...
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Why is iostream::eof inside a loop condition (i.e. `while (!stream.eof())`) considered wrong?
I just found a comment in this answer saying that using iostream::eof in a loop condition is "almost certainly wrong". I generally use something like while(cin>>n) - which I guess implicitly ...
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What is The Rule of Three?
What does copying an object mean?
What are the copy constructor and the copy assignment operator?
When do I need to declare them myself?
How can I prevent my objects from being copied?
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What are the basic rules and idioms for operator overloading?
Note: This question and the original answers are from 2010 and partially outdated. Most of it is still good and helpful, but the original text no longer covers everything there is to know about C++ ...
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Why should I not #include <bits/stdc++.h>?
I posted a question with my code whose only #include directive was the following:
#include <bits/stdc++.h>
My teacher told me to do this, but in the comments section I was informed that I ...
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Can a local variable's memory be accessed outside its scope?
I have the following code.
#include <iostream>
int * foo()
{
int a = 5;
return &a;
}
int main()
{
int* p = foo();
std::cout << *p;
*p = 8;
std::cout << *...
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Where and why do I have to put the "template" and "typename" keywords?
In templates, where and why do I have to put typename and template on dependent names?
What exactly are dependent names anyway?
I have the following code:
template <typename T, typename Tail> // ...
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Undefined, unspecified and implementation-defined behavior
What is undefined behavior (UB) in C and C++? What about unspecified behavior and implementation-defined behavior? What is the difference between them?
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1067
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What are the rules about using an underscore in a C++ identifier?
It's common in C++ to name member variables with some kind of prefix to denote the fact that they're member variables, rather than local variables or parameters. If you've come from an MFC background, ...
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What is array-to-pointer conversion aka. decay?
What is array-to-pointer conversion aka. decay? Is there any relation to array pointers?
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Why aren't variable-length arrays part of the C++ standard?
I haven't used C very much in the last few years. When I read this question today I came across some C syntax which I wasn't familiar with.
Apparently in C99 the following syntax is valid:
void foo(...
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