Different output for different compiler - C and C++ [duplicate]

Answer 1

Incompatibilities between ISO C and ISO C++

A common example is sizeof('A'), which is usually 4 in C but always 1 in C++, because character constants like 'A' have the type int in C but the type char in C++:

#include 

int main(void)
{
    printf("%d\n", sizeof('A'));
}