int main()
{int *a = new int(50);cout<<*a<<endl;delete a;delete a;return 0;
}

2）另外一个指针指向分配的内存，然后把这个2个指针都删除

int* p1 = new int(50);
int* p2 = p1; //p2和p1 现在指向同一内存地址
cout << *p1 << endl;
cout << *p2 << endl;
delete p1; //OK
delete p2; //ERROR! p2所指的内存，已通过delete p1而被释放，不可再delete一次

2、删除是一个普通指针或者不是一个指针

nt  a = 50;
int *p = &a;
delete p

2) 删除的不是一个指针

string ss = "chenyu";
delete ss;

3、删除了由系统释放