Java 实例 显示前n个或前 100 个素数

显示前n个素数的程序

import java.util.Scanner;class PrimeNumberDemo{   public static void main(String args[])   {      int n;      int status = 1;      int num = 3;      //For capturing the value of n      Scanner scanner = new Scanner(System.in);      System.out.println("Enter the value of n:");      //The entered value is stored in the var n      n = scanner.nextInt();      if (n >= 1)      {         System.out.println("First "+n+" prime numbers are:");         //2 is a known prime number         System.out.println(2);      }      for ( int i = 2 ; i <=n ;  )      {         for ( int j = 2 ; j <= Math.sqrt(num) ; j++ )         {            if ( num%j == 0 )            {               status = 0;               break;            }         }         if ( status != 0 )         {            System.out.println(num);            i++;         }         status = 1;         num++;      }            }}

输出：

Enter the value of n:15First 15 prime numbers are:23571113171923293137414347

显示前 100 个素数的程序

要显示前 100 个素数，你可以在上述程序中输入n值为 100 或者写一个这样的程序：

class PrimeNumberDemo{   public static void main(String args[])   {      int n;      int status = 1;      int num = 3;      System.out.println("First 100 prime numbers are:");         System.out.println(2);      for ( int i = 2 ; i <=100 ;  )      {         for ( int j = 2 ; j <= Math.sqrt(num) ; j++ )         {            if ( num%j == 0 )            {               status = 0;               break;            }         }         if ( status != 0 )         {            System.out.println(num);            i++;         }         status = 1;         num++;      }            }}

输出：

First 100 prime numbers are:2357111317192329313741434753596167717379838997101103107109113127131137139149151157163167173179181191193197199211223227229233239241251257263269271277281283293307311313317331337347349353359367373379383389397401409419421431433439443449457461463467479487491499503509521523541