C Program to Find the Size of a Union

/*
 * C program to find the size of a union
 */
#include <stdio.h>
 
void main()
{
    union sample
    {
        int   m;
        float n;
        char  ch;
    };
    union sample u;
 
    printf("The size of union = %d\n", sizeof(u));
    /*  initialization */
    u.m = 25;
    printf("%d %f %c\n", u.m, u.n, u.ch);
    u.n = 0.2;
    printf("%d %f %c\n", u.m, u.n, u.ch);
    u.ch = 'p';
    printf("%d %f %c\n", u.m, u.n, u.ch);
}

Output

 
The size of union = 4
25 0.000000 
1045220557 0.200000
1045220464 0.199999