下面程序的输出结果是 char *p1= “123”, *p2 = “ABC”, str［50］= "xyz"; strcpy（str+2,strcat（p1,p2））; cout << str; xyz123ABC z123ABC xy123ABC 出错
char *p1= “123”, *p2 = “ABC”, str［50］= "xyz"; strcpy（str+2,strcat（p1,p2））; cout << str;
分析：p1和p2指向的是常量存储区的字符串常量，没法连接，会有问题
