pointer in c++

Pointer: 

A pointer is a variable in C++ that stores another variable's memory address. Because they enable us to directly alter memory, pointers are powerful programming tools.

Example:

#include <iostream>

using namespace std;

int main() {

    int num = 10;

    int *ptr;

    ptr = &num; // assign the address of num to ptr

    cout << "Value of num is: " << num << endl;

    cout << "Address of num is: " << &num << endl;

    cout << "Value of ptr is: " << ptr << endl;

    cout << "Value pointed to by ptr is: " << *ptr << endl;

    *ptr = 20; // change the value of num through ptr

    cout << "Value of num is now: " << num << endl;

    return 0;

}

Output:

Value of num is: 10

Address of num is: 0x7ffd0589538c

Value of ptr is: 0x7ffd0589538c

Value pointed to by ptr is: 10

Value of num is now: 20