C语言详细分析讲解struct与union使用方法

#include <stdio.h>
 
struct TS
{
 
};
 
int main()
{
    struct TS t1;
    struct TS t2;
    
    printf("sizeof(struct TS) = %d\n", sizeof(struct TS));
    printf("sizeof(t1) = %d, &t1 = %p\n", sizeof(t1), &t1);
    printf("sizeof(t2) = %d, &t2 = %p\n", sizeof(t2), &t2);
    
    return 0;
}

#include<stdio.h>
#include<malloc.h>
 
struct SoftArray
{
    int len;
    int array[];
};
 
struct SoftArray* create_soft_array(int size)
{
    struct SoftArray* ret = NULL;
    
    if(size > 0)
    {
        ret = (struct SoftArray*)malloc(sizeof(struct SoftArray) + sizeof(int) * size);
        
        ret->len = size;
    }
    return ret;
}
 
void delete_soft_array(struct SoftArray* sa)
{
    free(sa);
}
 
void func(struct SoftArray* sa)
{
    int i = 0;
    
    if(NULL != sa)
    {
        for(i = 0; i < sa->len; i++)
        {
            sa->array[i] = i + 1;
        }
    }
}
 
int main()
{
    int i = 0;
    struct SoftArray* sa = create_soft_array(10);
    
    func(sa);
    
    for(i = 0; i < sa->len; i++)
    {
        printf("%d\n",sa->array[i]);
    }
    
    delete_soft_array(sa);
    
    return 0;
}

#include <stdio.h>
 
int system_mode()
{
    union SM
    {
        int i;
        char c;
    };
 
    union SM sm;
    
    sm.i = 1;
    
    return sm.c;
}
 
 
int main()
{
    printf("System Mode: %d\n", system_mode());
    return 0;
}