is Prime integer - Java java.lang

Java examples for java.lang:Math Number

  1. HOME
  2. Java
  3. java.lang
  4. Math Number

Description

is Prime integer

Demo Code


//package com.java2s;

public class Main {

    public static boolean isPrime(int x) {
        if (x <= 7) {
            if (x == 2 || x == 3 || x == 5 || x == 7)
                return true;
        }/* w  w w. ja  va 2  s  .c o  m*/
        int c = 7;
        if (x % 2 == 0)
            return false;
        if (x % 3 == 0)
            return false;
        if (x % 5 == 0)
            return false;
        int end = (int) Math.sqrt(x);
        while (c <= end) {
            if (x % c == 0) {
                return false;
            }
            c += 4;
            if (x % c == 0) {
                return false;
            }
            c += 2;
            if (x % c == 0) {
                return false;
            }
            c += 4;
            if (x % c == 0) {
                return false;
            }
            c += 2;
            if (x % c == 0) {
                return false;
            }
            c += 4;
            if (x % c == 0) {
                return false;
            }
            c += 6;
            if (x % c == 0) {
                return false;
            }
            c += 2;
            if (x % c == 0) {
                return false;
            }
            c += 6;
        }
        return true;
    }
}

Related Tutorials