判断是否是质数
package demo1;
import java.util.Scanner;
public class test19 {
public static void main(String[] args) {
Scanner sc=new Scanner(System.in);
System.out.println("请输入一个正整数");
int x= sc.nextInt();
boolean flag=true;
for(int i=2;i<=x-1;i++) {
if (x % i ==0) {
flag =false;
break;
}
}
if(flag){
System.out.println(x+"是质数");
}
else{
System.out.println(x+"不是质数");
}
}
}
