Question

#include <stdio.h>
int main()
{
    float a = 12.5;

    printf("%d\n", a);
    printf("%d\n", *(int *)&a);

    return 0;
}

Additionally, how do you interpret the expression *(int *)&a?

Answer 1

It takes the address of a float, casts it to an integer pointer and then dereferences that as an integer. Totally wrong.

There are at least two things wrong here:

• Nobody says the pointers for an int and a float need to be the same size
• The representation for a float looks nothing like the representation for a signed int

So the output to the second printf (if it doesn’t happen to crash since it’s undefined behavior, as per the first point) would likely be some strange, huge number.