Main.java Source code

Introduction

Here is the source code for Main.java

Source

//package com.java2s;
/**
 * Copyright 2010-present Facebook.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

public class Main {
    static public boolean isPrimeNumber(int num) {
        String reasons = whyNotPrimeNumber(num);
        return reasons == null;
    }

    static public String whyNotPrimeNumber(int num) {
        if (num <= 0) {
            return "0 and negative numbers are not Prime";
        }
        if (num == 1) {
            return "1 is not prime number";
        }

        for (int i = (int) Math.sqrt(num); i > 1; i--) {
            if (num % i == 0) {
                return num + " = " + i + " X " + num / i;
            }
        }
        return null;
    }
}