Question

#include<stdio.h>

union node {
     int i;
     char c[2];
};

main() {

    union node n;
    n.c[0] = 0;
    n.c[1] = 2;
    printf("%d\n", n.i);
    return 0;
}

I think it gives 512 output becouse c[0] value stores in first byte and c[1] value stores in second byte, but gives 1965097472. Why ?.
I compiled this program in codeblocks in windows.

Answer 1

Your union allocates four bytes, starting off as:

[????] [????] [????] [????]

You set the least two significant bytes:

[????] [????] [0x02] [0x00]

You then print out all four bytes as an integer. You’re not going to get 512, necessarily, because anything can be in those most significant two bytes. In this case, you had:

[0x75] [0x21] [0x02] [0x00]