java - 计算素数(新手)

Question

该程序检查用户输入的数字是否为素数。

我的问题在if语句中。由于某些原因，Boolean永远不会切换。如果数字为质数，则只会给出两个结果。

我想念什么？

import java.util.Scanner;
public class Prime 
{

     public static void main(String[] args)
    {
       System.out.println("Enter a number to check if it is prime:");
       Scanner kb = new Scanner(System.in);
       int n = kb.nextInt();
       boolean more = true;

       do
       {
           for (int i = 2; i <= n; i++)
           {
               if (n <=1 || n%i==0) 
               {
                    System.out.println(n + " is not prime");
                    more = false;
               }              
            } 
       }
       while (more);
       System.out.println(n + " is prime");
    }
}

Answer 1

删除if()内部的打印件，并在do while循环后使用以下代码

if(more)
 System.out.println(n + " is prime");
else
 System.out.println(n + " is not prime");

并且您也不需要do while循环将其删除。完整代码

 System.out.println("Enter a number to check if it is prime:");
 Scanner kb = new Scanner(System. in );
 int n = kb.nextInt();
 boolean more = true;


 for (int i = 2; i <= n / 2; i++) {
    if (n <= 1 || n % i == 0) {

        more = false;
        break;
    }
 }
 if (more) System.out.println(n + " is prime");
 else System.out.println(n + " is not prime");

Demo