几个有意思的基础C题

几个有意思的基础C题，结果需要深思

[root@ethan lua]# cat testsh.cpp
#include<iostream>
using namespace std;
union t
{
        int i;
        char str[2];
};
union myun
{
 struct {int x; int y; int z;} u;
 int k;
 int j;
}a;
int main()
{
        t test;
        test.i=0;
        test.str[0]=20;
        test.str[1]=1;
//      cout <<"str[0]=" << test.str[0] << " str[1]=" << test.str[1] << endl;
        cout << "test.i = " << test.i << endl;

        a.u.x = 4;
        a.u.y = 5;
        a.u.z = 6;
        a.k = 0;
        cout << a.u.x << " " << a.u.y << " " << a.u.z << endl;
        a.j = 1;
        cout << a.u.x << " " << a.u.y << " " << a.u.z << endl;

        char a[] = "abc";
        char *pa = "abc";
        char b[] = "abc";
        //char *pa = "abc";
        char *pb = "abc";
        const char c[] = "abc";
        const char* ppa = "abc";
        const char d[] = "abc";
        //const char* ppa = "abc";
        const char* ppb = "abc";
        cout << (a == b) << endl;
        cout << (pa == pb) << endl;
        cout << (c == d) << endl;
        cout << (ppa == ppb) << endl;
        return 0;
}

[root@ethan lua]# ./testsh

test.i = 276 //字符间数据是相加的。。？

0 5 6

1 5 6 //联合体永远替换同空间

0

1

0

1