Question

分配是关于尝试从用户输入的内容中获取素数，并且我试图通过用户输入0来结束循环

/*
 Natasha Shorrock
 Assignment A4
 10/20/16
 */
package a4;

import java.util.Scanner;

public class MainApp {

        static boolean isPrimeOptimized(int candidate) {
        if (candidate < 2) {
            return false;
        }//if
        if (candidate % 2 == 0) {
            //divisble by 2 with no remainder
            //is not prime
            return false;
        }//if
        int divisor = 3;
        while (divisor < candidate / 2) {
            if (candidate % divisor == 0) {
                return false;// this is not prime
            }//if
            divisor = divisor + 2;
        }//while
        return true;
    }//isPrime

    public static void main(String[] args) {
        while (true) {
            Scanner sc = new Scanner(System.in);
            System.out.println("Enter 2 numbers or zero to exit: ");

            //ask the user for low and high
            //range of [prime numbers to generate
            int low = sc.nextInt();
            int high = sc.nextInt();

            int candidate = low;
            int count = 0;
            while (candidate <= high) {
                if (isPrimeOptimized(candidate)) {
                    //if prime print
                    count = count + 1;
                    System.out.println();
                    System.out.println(count + " " + candidate);

                }//if
                candidate = candidate + 1;
            }//while

        }//while (true)

    }//class

}//classMainApp

Answer 1

由于您只需要退出一个号码0，因此只会填充low并等待high。因此if应位于两次扫描之间，并且只应检查low

在if下添加low语句，以检查它是否为0。

int low = sc.nextInt();
if(low == 0){
    break;
}

Answer 2

首先，即使用户输入0，您也要强制他们输入两个数字：

int low = sc.nextInt();
int high = sc.nextInt();

我建议你在代码中执行以下操作：

int low = sc.nextInt();
if(low==0){
   return 0;
} else{

   int high = sc.nextInt();
   //rest of your code and while loop
}

尝试结束用户“0”的循环

2 个答案: