C program to find the size of a union

/* Write a  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);
}     /*End of main() */

/*-----------------------------------------
Output
The size of union =4
25 12163373596672.000000
-13107 0.200000 Í
-13200 0.199999 p
------------------------------------------*/