检查列表有多少是正数[关闭]

Question

编写一个名为 PositiveNegative 的程序，该程序读取未指定数量的整数，确定输入了多少个正值和负值，并计算输入值的总和和平均值（不计算零）。当用户输入 0（零）时，输入的读取结束。显示正负输入的数量、总和和平均值。平均值应计算为浮点数。设计程序，使其在每组条目后询问用户是否要继续输入新的输入，仅当他们没有以“是”回答问题时才结束程序。

这是一个示例运行：

Input a list of integers (end with 0): 1   2   -1   3   0

# of positive inputs:   3
# of negative inputs:   1
The total:              5.0
The average:            1.25

Would you like to continue with new inputs? yes
Input a list of integers (end with 0): 0

No numbers were entered except 0

Would you like to continue with new inputs? no

这是我的代码：

import java.util.*;

public class PositiveNegative
{
  public static void main(String[] args){

      Scanner input = new Scanner(System.in);
      String answer;
      int countpositive = 0;
      int countnegative = 0;
      int total = 0;
      int num = 0;

      System.out.print("Input a list of integers (end with 0): ");

      do{
         String list = input.nextLine();

         for(int i = 0; ; i=i+2 ){
            num = Integer.parseInt(list.substring(i,i+1));

            if( num == 0)
               break;
            else if ( num > 0)
               countpositive++;
            else if ( num < 0)
               countnegative--;
            total = total + num;
            }
            double average = total/(countpositive + countnegative); 
            System.out.println("# of positive inputs: "+countpositive);
            System.out.println("# of negative inputs: "+countnegative);
            System.out.println("The total: "+total);
            System.out.println("The average"+average);
            System.out.println("\n ");
            System.out.print("Would you like to continue with new inputs? ");
            answer = input.next();

         }while(answer.equalsIgnoreCase("Yes"));

       }
   }  

我可以编译文件，但是当我运行它时，我无法获得像示例运行那样的结果。

Answer 1

当遇到负整数时，您正在递减 (countnegative--;) 负整数的计数，而不是递增 (countnegative++;)。