Question

What is wrong in that: I just wanted to pointers to int and give that ints value of 0.

    int* p;int* q;

*p = 0; *q = 0;
cout<<"p = "<<*p<<" q = "<<*q<<endl;

This is annoying

WORKS:

int* p;
   *p = 0;

   cout<<*p<<endl;

CRASHES:

     int* p;
   int* q;
   *p = 0;
   *q = 0;

   cout<<*p<<endl;

Answer 1

To use a pointer, that pointer has to point to something. So there are two steps: create the pointer, and create the thing it points to.

int *p, *q;    // create two pointers
int a;         // create something to point to
p = &a;        // make p point to a
*p = 0;        // set a to 0
q = new int;   // make q point to allocated memory
*q = 0;        // set allocated memory to 0