// This program uses two functions that accept
// addresses of variables as arguments.
#include <iostream>
using namespace std;

// Function prototypes
void getNumber(int *);
void doubleValue(int *);

int main()
{
    int number;

    // Call getNumber and pass the address of number.
    getNumber(&number);

    // Call doubleValue and pass the address of number.
    doubleValue(&number);

    // Display the value in number.
    cout << "That value doubled is " << number << endl;
    return 0;
}

//******************************************************
// Definition of getNumber. The parameter, input, is a *
// pointer. This function asks the user for a number.  *
// The value entered is stored in the variable         *
// pointed to by input.                                *
//******************************************************

void getNumber(int *input)
{
     cout << "Enter an integer number: ";
     cin >> *input;
}

//******************************************************
// Definition of doubleValue. The parameter, val, is a *
// pointer. This function multiplies the variable      *
// pointed to by val by two.                           *
//******************************************************

void doubleValue(int *val)
{
     *val *= 2;
}