example.cpp

/**
 * Copyright (c) 2013, Krzysztof Kliś <krzysztof.klis@gmail.com>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <iostream>
#include <cmath>
#include <cstdlib>
#include "contract.hpp"

using namespace std;

// Calculate greatest common divisor of two integers
int gcd(int a, int b)
{
    REQUIRES(a != 0 || b != 0)
    int result;

    if (b == 0) {
        result = a;
    } else {
        result = gcd(b, a % b);
    }

    ENSURES((a % result == 0) && (b % result == 0))
    return result;
}

int main(int argc, char *argv[])
{
    try {
        while(true) {
            int a = rand() % 100;
            int b = rand() % 100;
            cout << a << "," << b << ":";
            cout << gcd(a,b) << endl;
        }
    } catch (contract::exception& e) {
        cout << endl << e.what() << endl;
    }
    return 0;
}