Question

In following case I get NumRecPrinted = 0 , that is num is 0

int main()
{
    int demo(int *NumRecPrinted);
    int num = 0;
    demo(&num);
    cout << "NumRecPrinted=" << num;    <<<< Prints 0
    return 0;
}

int demo (int *NumRecPrinted)

{
    int no_of_records = 11;
    NumRecPrinted = &no_of_records;
}

Answer 1

You are assigning the address to the pointer, and not the value to the pointed-to. Try it like this instead

int demo (int *NumRecPrinted)
{
     int no_of_records = 11;
     *NumRecPrinted = no_of_records; 
}