pointer’s pointer

#include <iostream>

using namespace std;

void GetMem(char** p, int n)
{
    *p = (char*)malloc(sizeof(char)*n);
};

void main()
{
    char c[] = "a";
    char* ptr = c;//NULL;
    GetMem(&ptr, 100);
    strcpy(ptr,"hello!");
    cout << ptr << endl;
    cout << *ptr << endl;
    cout << &ptr << endl;
}

see the procedure:

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