素数

Source: Dev.to

什么是质数？

重要说明

• 小于或等于 1 的数字不是质数

JavaScript

let num = Number(prompt("Enter a number: "));
let div = 2;
let flag = true;

while (div  1) {
    console.log("This number is Prime");
} else {
    console.log("This number is not Prime");
}

输出：

Python

num = int(input("enter a number: "))
div = 2
flag = True
while div <= num / 2:
    if num % div == 0:
        flag = False
        break
    div += 1
if flag == True:
    print("This number is Prime")
else:
    print("This number is not Prime")

输出：

Java

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);
        System.out.print("Enter a number: ");
        int num = sc.nextInt();

        boolean flag = true;

        if (num <= 1) {
            flag = false;
        } else {
            for (int i = 2; i <= Math.sqrt(num); i++) {
                if (num % i == 0) {
                    flag = false;
                    break;
                }
            }
        }

        if (flag) {
            System.out.println("This number is Prime");
        } else {
            System.out.println("This number is not Prime");
        }

        sc.close();
    }
}

输出：