C语言实验之判断素数（循环结构java)方法讲解

Problem Description

从键盘上输入任意一个正整数，然后判断该数是否为素数。

如果是素数则输出"This is a prime."

否则输出“This is not a prime.”

Input

输入任意一个正整数n(1 <= n <= 1000000)。

Output

判断n是否为素数，并输出判断结果：

如果n是素数则输出"This is a prime."

否则输出“This is not a prime.”

Sample Input

3

Sample Output

This is a prime.

package practice;  
  
import java.util.Scanner;  
  
public class Main {  
  
    public static void main(String[] args) {  
        // TODO Auto-generated method stub  
        int n,i,f=1;  
        Scanner sc = new Scanner(System.in);  
        n = sc.nextInt();  
        if(n==1) {  
            System.out.println("This is not a prime.");  
        }  
        else if(n==2) {  
            System.out.println("This is a prime.");  
        }  
        else {  
            for(i=2;i<n;i++) {  
                if(n%i==0) {  
                    f=0;  
                }  
            }  
            if(f==0) {  
                System.out.println("This is not a prime.");  
            }  
            else {  
                System.out.println("This is a prime.");  
            }  
        }  
        sc.close();  
  
    }  
  
}