Question

我一直在努力弄清楚这段代码，但似乎无法修复它：

import java.util.Scanner;

public class Graphs
{
 public void drawHistograms()// draws 5 histograms
 {
  Scanner input = new Scanner( System.in );

  int number1 = 0; // first number
  int number2 = 0; // second number
  int number3 = 0; // third number
  int number4 = 0; // fourth number
  int number5 = 0; // fifth number

  int inputNumber; // number entered by user
  int value = 0; // number of stars to print
  int counter = 1; // counter for current number

  while ( counter <= 5 )
  {
     System.out.println( "Enter number: " );
     inputNumber = input.nextInt();

     // define appropriate num if input is between 1-30
     if ( inputNumber >= 1 && inputNumber <= 30 )
     {
        switch ( inputNumber )
        {
           case 1:
              number1 = inputNumber;
              break; // done processing case

           case 2:
              number2 = inputNumber;
              break; // done processing case

           case 3:
              number3 = inputNumber;
              break;
           case 4:
              number4 = inputNumber;
              break; // done processing case

           case 5:
              number5 = inputNumber;
              break; // done processing case
        }counter++;

     } // end if
     else
        System.out.println(
           "Invalid Input\nNumber should be between 1 and 30" );
  } // end while

  // print histograms
  for ( counter = 0; counter <= 4; counter++ )
  {
     switch ( counter )
     {
        case 1:
           value = number1;
           break; // done processing case

        case 2:
           value = number2;
           break; // done processing case

        case 3:
           value = number3;
           break; // done processing case

        case 4:
           value = number4;
           break; // done processing case

        case 5:
           value = number5;
           break; // done processing case
     }

     for ( int j = 0; j <= value; j++ )
       {
        System.out.print( "*" );

       } System.out.println();       
  } // end for loop
} // end method drawHistograms
} // end class Graphs

我的输出应该是这样的：

Enter number: 5
Enter number: 2
Enter number: 8
Enter number: 4
Enter number: 6
*****
**
********
****
******

关于如何解决此问题的任何想法？我很难过。我已经尝试更改开关中的变量，看看输出会发生什么变化;无论我输入什么数字，我都会得到几乎相同的东西。

Answer 1

我看到以下两个问题：

您的第一个switch也应该启用counter而不是inputNumber。
对于第二个switch周围的循环，您应该从1到5而不是0到4循环。

旁注：最好使用列表或数组来存储5个数字，而不是为每个数字使用单独的变量。

Answer 2

首先，你不需要switch。考虑以下方法

public void drawHistograms() {
    Scanner input = new Scanner(System.in);
    int[] number = new int[5]; // define an array
    int inputNumber;
    int counter = 0; // set counter to 0
    while (counter <= 4) {
        System.out.println("Enter number: ");
        inputNumber = input.nextInt();
        if (inputNumber >= 1 && inputNumber <= 30) { // if input is valid
            number[counter] = inputNumber; // add that value to array
        } else {
            System.out.println("Number should be between 1 and 30");
        }
        counter++; // increment counter
    }
    // now your array contains all inputs
    for (int i = 0; i < number.length; i++) { // iterate array
        for (int j = 0; j < number[i]; j++) {// iterate up to element value
            System.out.print("*");
        }
        System.out.println("");
    }
}

如何正确使用包括扫描仪实用程序在内的开关？

2 个答案: