Question

我无法获得第二个正确的数字。 “ if”语句中有问题。谁能发现它？当我输入2 3 4 or 4 3 2但没有像 6 -5 4 那样混乱时，它可以工作。如果我执行 6 -5＆4 ，则输出为 -5 -5 6

import java.util.*; // imported scanner
public class ThreeNumbers{

   public static void main(String[] args){

      Scanner input = new Scanner(System.in);

        // Prompt the user to enter three floating-point numbers
        System.out.print("Enter 3 numbers separated by a space: ");
        int num1 = input.nextInt();
        int num2 = input.nextInt();
        int num3 = input.nextInt();


        // Display inputs in sorted order
        System.out.print("Sorted numbers: ");

        // Find the minimum number input by the user
        if ((num1 < num2) && (num1 < num3)) {
            System.out.print(num1 + " ");
        } else if ((num2 < num1) && (num2 < num3)) {
            System.out.print(num2 + " ");
        } else if ((num3 < num1) && (num3 < num2)) {
            System.out.print(num3 + " ");

        }
        // Find the middle number input by the user
        if ((num1 != num2) && (num1 != num3) && (num1 >= num2) && (num1 <= num2)) {
            System.out.print(num1 + " ");
        } else if ((num2 != num1) && (num2 != num3)) {
            System.out.print(num2 + " ");
        } else if ((num3 != num1) && (num3 <= num2)) {
            System.out.print(num3 + " ");

        }
        // find the maximum number input by the user
        if ((num1 > num2) && (num1 > num3)) {
            System.out.print(num1 + " ");
        } else if ((num2 > num1) && (num2 > num3)) {
            System.out.print(num2 + " ");
        } else if ((num3 > num1) && (num3 > num2)) {
            System.out.print(num3 + " ");

Answer 1

注释说明：

// Find the middle number input by the user
    if ((num1 != num2) && (num1 != num3) && (num1 >= num2) && (num1 <= num2)) {
    // This is never true. If num1 != num2 , it cannot be >= AND <=
        System.out.print(num1 + " ");
    } else if ((num2 != num1) && (num2 != num3)) {
    // 6 != -5 and -5 != 4 => hit --> -5 ?? Logic Error!!
        System.out.print(num2 + " ");
    } else if ((num3 != num1) && (num3 <= num2)) {
        System.out.print(num3 + " ");

我建议使用Array.sort，数学的最小/最大方法，或者如果必须使用if：

int min = int.Max;
// unreadable:
//min = num1 < num2 ? (num1 < num3 ? num1: num3) : (num2 < num3 ? num2 : num3);
// still pretty bad:
if( num1 < num2 ){
  if ( num1 < num3 ) {
    min = num1;
  } else {
    min = num3;
  }
} else {
  if ( num2 < num3 ) {
    min = num2;
  } else {
    min = num3;
  }
}
// OR
int min = int.Max;
if ( num1 < min ) min = num1;
if ( num2 < min ) min = num2;
if ( num3 < min ) min = num3;

分别代表最大，中间是那个，既不是最小也不是最大：

int mid = num1+num2+num3-min-max;

Answer 2

认为您的问题可能出在(num1 >= num2) && (num1 <= num2)上，因为您的条件之一为false（即6是> = -5，但不是<= -5）。

为什么要使用if语句来执行此操作，所以您的实现似乎非常复杂（尤其是如果您突然想输入更多的数字）。代替所有这些if语句，只需将每个输入存储到一个整数数组中，对其进行排序并打印出来即可。

public static void main(String [] args) {
  Scanner input = new Scanner(System.in);
  System.out.print("Enter 3 numbers separated by a space: ");
  int [] inputNumbers = new int[3];
  inputNumbers[0] = input.nextInt();
  inputNumbers[1] = input.nextInt();
  inputNumbers[2] = input.nextInt();
  Arrays.sort(inputNumbers);
  System.out.println(Arrays.toString(inputNumbers));
}

Answer 3

对于中间数字，如果条件不正确，则使用第一个数字作为中间数字，您将得到输出

if ((num1 != num2) && (num1 != num3) && (num1 >= num2) && (num1 <= num3))

Answer 4

尝试一下：

if (((num1 >= num2) && (num1 <= num3)) || ((num1 <= num2) && (num1 >= num3))) {
        System.out.print(num1 + " ");
    } else if (((num2 >= num1) && (num2 <= num3))||((num2 <= num1) && (num2 >= num3))) {
        System.out.print(num2 + " ");
    } else if (((num3 >= num1) && (num3 <= num2))||((num3 <= num1) && (num3 >= num2))) {
        System.out.print(num3 + " ");

    }

我需要在第二个“ if”语句中进行哪些更改？

4 个答案: