Explain the concept of union of structures in C language

If the structure is nested inside a union, it is called as a union of structures. There is a possibility to create a union inside a structure in C programming language.

Example

Following is the C program for union of structures −

#include<stdio.h> struct x {    int a;    float b; }; union z{    struct x s; }; main ( ){    union z u;    u.s.a = 10;    u.s.b = 30.5;    printf("a=%d", u.s.a);    printf("b=%f", u.s.b);    getch ( ); }

Output

When the above program is executed, it produces the following result −

a= 10 b = 30.5

Example

Given below is another C program for union of structures −

#include<stdio.h> union abc{    int a;    char b; }v; int main(){    v.a=90;    union abc *p=&v;    printf("a=%d
",v.a);//90    printf("b=%c
",v.b);//Z    printf("a=%d b=%c
",p->a,p->b);//90 Z    printf("%d",sizeof(union abc));//4    return 0; }

Output

When the above program is executed, it produces the following result −

a=90 b=Z a=90 b=Z 4