c联合体

// Online C compiler to run C program online
#include <stdio.h>

typedef union
{
    char c;
    int i;
}u_t;

int main() {

    u_t u;
    u.c = 1;
    
    printf("u.c = %d, sizeof(u.c) = %d\n", u.c, sizeof(u.c));
    printf("u.i = %d, sizeof(u.i) = %d\n", u.i, sizeof(u.i));
    printf("sizeof(u_t) = %d\n\n", sizeof(u_t));
    
    u.c = 2;
    printf("u.c = %d, sizeof(u.c) = %d\n", u.c, sizeof(u.c));
    printf("u.i = %d, sizeof(u.i) = %d\n", u.i, sizeof(u.i));
    printf("sizeof(u_t) = %d\n\n", sizeof(u_t));    
    
    return 0;
}