#include <iostream.h>

void main () {

int var_a;    // define a variable a 
int *ptrA;   // define a pointer, note the use of *
var_a = 6;   // initialise the variable 
ptrA = &var_a;   // assign the the pointer to the address of the variable 
*ptrA = 12;       // use the pointer to change the value of the variable
cout << var_a << endl;     // print the new value of the variable

}