Why does Visual Studio 2013 error on C4996?

Apparently new projects enable "SDK check" by default now, which treats these warnings as errors. To disable it, go to project properties -> Configuration Properties -> C/C++ -> General -> SDL checks -> No.

You can also disable specific warning numbers in C/C++ > Advanced > Disable Specific Warnings.

enter at the beginning of the program:

#pragma warning(disable : 4996)

and that's it.