Question

How to use anonymous union within struct in C

Answer 1

#include <stdio.h>
#include <string.h>
#include <stdbool.h>
 
typedef struct TEST {
    bool b;
    union  {
        long n;
        char s[12];
        float f;
    };
} TEST;
 
int main() {
    TEST t;
     
    printf("size: %d\n\n", sizeof(t));
      
 
    t.b = true;
 
    t.n = 8493;
    printf("(set)t.b:%s\n", t.b ? "true" : "false");
    printf("(set)t.n: %d\n", t.n);
    printf("t.s: %s\n", t.s);
    printf("t.f: %f\n", t.f);
    printf("size: %d\n\n", sizeof(t));
 
    strcpy(t.s, "c union");
    printf("(set)t.b:%s\n", t.b ? "true" : "false");
    printf("t.n: %d\n", t.n);
    printf("(set)t.s: %s\n", t.s);
    printf("t.f: %f\n", t.f);
    printf("size: %d\n\n", sizeof(t));
      
    t.f = 3.14;
    printf("(set)t.b:%s\n", t.b ? "true" : "false");
    printf("t.n: %d\n", t.n);
    printf("t.s: %s\n", t.s);
    printf("(set)t.f: %f\n", t.f);
    printf("size: %d\n\n", sizeof(t));
     
    return 0;
}
  
 
  
  
/*
run:
  
size: 24

(set)t.b:true
(set)t.n: 8493
t.s: -!
t.f: 0.000000
size: 24

(set)t.b:true
t.n: 1853169763
(set)t.s: c union
t.f: 18965745136684753516509528064.000000
size: 24

(set)t.b:true
t.n: 1078523331
t.s: ��H@ion
(set)t.f: 3.140000
size: 24
  
*/

 

70+ SQL courses for beginners and professionals