This C Program finds the size of a union. The program uses sizeof() keyword to get the size.
Here is source code of the C program to find the size of a Union. The C program is successfully compiled and run on a Linux system. The program output is also shown below.

/*
* 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);
}

$ cc pgm94.c
$ a.out
The size of union = 4
25 0.000000 
1045220557 0.200000
1045220464 0.199999