/*
 * -----------------------------------------------------
 * CS2S03/SE2S03, September 2011
 * Assignment 1, Question 1
 * File: PE0106.cpp
 * -----------------------------------------------------
 * This program reads an integer and then displays the
 * number that has the same digits in the reverse order.
 * -----------------------------------------------------
 */

#include "genlib.h"
#include "simpio.h"
#include <iostream>

/* Private function prototypes */

long DigitReverse(long n);

/* Main program */

int main() {
    long n;

    cout << "This program reverses the digits in an integer." << endl;
    while (true) {
        cout << "Enter a positive integer: ";
        n = GetLong();
        if (n > 0) break;
        cout << "Try again." << endl;
    }
    cout << "The reversed integer is: " << DigitReverse(n) << endl;

    return 0;
}

/*
 * Function: DigitReverse
 * Usage: rev = DigitReverse(n);
 * -----------------------------------------------------
 * This function returns the integer that has the same
 * digits as n but in reverse order
 */

long DigitReverse(long n) {
    long reverse = 0;
	
    while (n > 0) {
        reverse = reverse * 10 + (n % 10);
        n = n / 10;
    }
	
    return reverse;
}