/*
    testfunc04.cpp
    CIS 150
    2008-06-10
    David Klick
   
    This program demonstrates how to create
    an absolute value function for integers.
*/

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

void cont();
int absval(int x);   // function prototype 

int main(int argc, char* argv[]) {
    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";
    cont();
    return 0;
}

/*
    int absval(int a);
   
    Arguments:
        int a: an arbitrary integer value
   
    Returns: the absolute value of the argument

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

/*
    void cont();
   
    Arguments: none
   
    Returns: nothing
   
    Clears input buffer and pauses waiting for user 
    to press Enter.
*/
void cont() {
    if (cin.rdbuf()->sungetc() != -1 && cin.get() != '\n') cin.ignore(80,'\n');
    cout << "Press enter to continue...";
    cin.get();
}