C语言基础语法第八章结构体demo8.13共用体注意数据覆盖的问题.c

在这里插入代码片#include <stdio.h>

struct TestT
{
	int idata;
	char cdata;
	int ddata;
};
 
union TestU
 {
	int idata;
	char cdata;
	int ddata;
 };

int main()
{
	struct TestT t1;
	union TestU u1;
	printf("结构体t1的大小是：%d\n",sizeof(t1));
    printf("联合体u1的大小是：%d\n",sizeof(u1));
	printf("\n");
	
	t1.idata=10;
	t1.cdata='a';
	t1.ddata=30;
	printf("idata:%p,%d\n",&t1.idata,t1.idata);
	printf("cdata:%p,%d\n",&t1.cdata,t1.cdata);
	printf("ddata:%p,%d\n",&t1.ddata,t1.ddata);
	
	printf("\n");
	u1.idata = 10;//数据覆盖 idata的值是 30
	u1.cdata = 'a';
	u1.ddata = 30;
	printf("idata = %d\n",u1.idata);
	printf("cdata = %d\n",u1.cdata);
	printf("ddata = %d\n",u1.ddata);
	
	printf("idata:%p\n",&u1.idata);
	printf("cdata:%p\n",&u1.cdata);
	printf("ddata:%p\n",&u1.ddata);
	return 0;
}