C++ Implementation Behaviors

behavior of some syntax that is left up to the implementation(compiler) to define.

#include <iostream>
 
int main()
{
	std::cout << sizeof(int) << '\n'; // print how many bytes of memory an int value takes
 
	return 0;
}

On some compilers, it will produce 4, on others it may produce 2

Unspecified Behaviors

Very very similar to implementation behaviors, but the implementation is not required to document the behavior. might just be a C++ default difficulty