/*
   testfunc04.cpp
   CIS 150
   6/9/2005
   David Klick
   
   This program demonstrates how to create
   an absolute value function for integers.
*/

#include <iostream>
#include <iomanip>
#include <cctype>    // for toupper
using std::cout;
using std::cin;

int absval(int x);   // function prototype 

int main(void) {
   char choice;
   int num1;
   do {
      // get value to convert from user
      cout << "Enter an integer: ";
      cin >> num1;
      
      // get absolute value and display it
      cout << "The absolute value of " << num1
           << " is " << absval(num1) << '\n';
           
      // find out if user wants to keep going
      do {
         cout << "\nCalculate another value? (Y/N) ";
         cin >> choice;
         choice = toupper(choice);
         // check for invalid user entry
         if (choice != 'Y' && choice != 'N') {
            cout << "Error: Invalid choice\n";
         }
      } while (choice != 'Y' && choice != 'N');
   } while (choice == 'Y');
   
   cout << "\nNormal program termination\n";
   return 0;
}

/*
   This function calculates and returns
   the absoulute value of an integer.
*/
int absval(int a) {
   return a>=0 ? a : -a;
}