c++ #include bits/stdc++.h

#include <bits/stdc++.h>

This line includes the entire standard library in C++, providing access to all its functionalities without explicitly calling each header file. It's commonly used in competitive programming or quick coding exercises for its convenience.

This method isn't part of the standard C++ library and might not work on all compilers. It's considered non-portable and discouraged in larger projects due to potential compatibility issues across different systems and compilers.