Java:使用模运算符的交换机不可达语句

Question

我正在尝试完成一个hackerrank算法挑战，它将在一系列交替的天气模式之后预测树的高度。我不知道为什么我的逻辑不起作用。Java说我的switch语句中的断点不起作用。我已经完整地粘贴了下面的代码。

import java.util.Scanner;

public class Main {

public static void main(String[] args) {
    Scanner scan = new Scanner(System.in);
    int i = scan.nextInt(); // user input how many test cases
    System.out.println("test cases set.");
    int[] cycles = new int[i];

    for (int x = 0; x < i; x++) {
        cycles[x] = scan.nextInt(); // user input test cycles
    }


    for (int x = 0; x < i; x++) {
        System.out.println(cycles[x]);
        int temp = predictor(cycles[x]);
        System.out.println(temp);
    }
}


public static int predictor(int cycles) {
    // determines the remainder to find even or odd cycle year
    int heightRemainder = cycles % 2;

    switch (heightRemainder) {
        case 0:
            System.out.println("Even number");
            return cycles; // UNREACHABLE, cycles is a temp variable to check functionality
            break;


        case 1:
            System.out.println("Odd number");
            return cycles; // UNREACHABLE, same here
            break;
    }
    return -1;
  }
}

Answer 1

是的，它不会工作，因为你的break语句在return语句之后，执行控制不会转到break语句。

在切换情况下不是返回，而是使用变量来存储循环值，然后在方法结束时返回该变量，如下所示

public static int predictor(int cycles) {
// determines the remainder to find even or odd cycle year
int heightRemainder = cycles % 2;
 int r=-1;


switch (heightRemainder) {
    case 0:
        System.out.println("Even number");
        r =cycles; 
        break;


    case 1:
        System.out.println("Odd number");
         r=cycles
        break;
     }
    return r;
  }
 }

Answer 2

在predictor方法中:删除break；语句...这是死代码，因为您返回的是循环值

switch (heightRemainder) {
        case 0:
            System.out.println("Even number");
            return cycles; // UNREACHABLE, cycles is a temp variable to check functionality
          case 1:
            System.out.println("Odd number");
            return cycles; // UNREACHABLE, same here
  }