Prime.java

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/*
    Synthia, a data structure generator
    Copyright (C) 2019-2021 Laboratoire d'informatique formelle
    Université du Québec à Chicoutimi, Canada
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU Lesser General Public License as published
    by the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.
 
    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Lesser General Public License for more details.
 
    You should have received a copy of the GNU Lesser General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package examples.quickcheck;
 
import ca.uqac.lif.synthia.random.RandomFloat;
import ca.uqac.lif.synthia.random.RandomInteger;
import ca.uqac.lif.synthia.test.Assert;
 
/**
 * Simple illustration of the shrinking process on randomly generated integers.
 * @ingroup Examples
 * @author Sylvain Hallé
 *
 */
public class Prime
{
    public static void main(String[] args)
    {
        Assert<Integer> a = new Assert<Integer>(new RandomInteger(0, Integer.MAX_VALUE), new RandomFloat()) {
            protected boolean evaluate(Integer x) {
                return !isPrime(x);
            }
        };
        if (!a.check())
        {
            System.out.println("Assertion is false");
            System.out.println(a.getInitial() + " is prime");
            System.out.println(a.getIterations().size() + " shrinking steps");
            System.out.println(a.getShrunk() + " is also prime");
        }
    }
 
    /**
     * Checks if an integer is prime.
     * @param n The integer
     * @return {@code true} if the integer is prime, {@code false} otherwise
     */
    public static boolean isPrime(int n)
    {
        if (n < 2)
        {
            return false;
        }
        for (int x = 2; x < n / x; x++)
        {
            if (n % x == 0)
            {
                return false;
            }
        }
        return true;
    }
}