java - do while 循环出现逻辑错误

Question

有人可以帮我解决我的逻辑错误吗？我很新，确实需要一些帮助。这是一个介绍类的简单程序(我想这是非常明显的)。我希望用户留在循环中，除非他们输入 -99 退出。然后它将显示最高和最低的条目。

谢谢!

import java.util.Scanner;

public class LeastGreatest {

    public static void main(String[] args) {

      Scanner keyboard = new Scanner(System.in);
        int input = 0, high = 0, low = 0;

        System.out.println("Welcome to fun with Loops and Numbers!\n");
      System.out.println("Please Enter the AN INTEGER: \n");
        input = keyboard.nextInt();

        high = input;
        low = input;
        //System.out.println(input);
        do
        {
            System.out.println("Please Enter the AN INTEGER (Press -99 to Exit): \n");
            input = keyboard.nextInt();

            if (input > high)
            {
                input = high;
            }
            if (input < low)
            {
                input = low;
            }
        } while(input != -99);

        System.out.println("The highest INT entered was: " + high);
        System.out.println("The lowest INT entered was: " + low);
        System.out.println("Thank You! Goodbye!");      
    }
}

Answer 1

您正在重复分配 input恢复到原来的值:

high = input;
low = input;
...
if (input > high)
{
  input = high; // input = input
}
if (input < low)
{
  input = low; // input = input
}

这是正确的:

if (input > high)
{
  high = input;
}
if (input < low)
{
  low = input;
}

此外，假设input < -99无效，最低值始终为 -99。以下内容将纠正此问题:

while (input != -99) { // Break BEFORE setting low to -99.
  if (input > high)
  {
    high = input;
  }
  if (input < low)
  {
    low = input;
  }

  System.out.println("Please Enter the AN INTEGER (Press -99 to Exit): \n");
  input = keyboard.nextInt();
}