java - 使用小于零的数字进行计算

Question

如果这个问题确实很明显，但我已经尝试了一切，请原谅。

我正在尝试制作一个计算数字百分比的计算器。

但是当我使用此代码时，它一直输出 0:

import java.io.*;

class pCalc {
     public static void main(String args[])
     {
          InputStreamReader istream = new InputStreamReader(System.in) ;
          BufferedReader bufRead = new BufferedReader(istream) ;

          System.out.println("Hello...");

          try {
               System.out.println("Please Enter In The Percentage You Want To Find (e.g 25): ");
               String rpercent = bufRead.readLine();

               System.out.println("Please Enter In The Number You Wish To Find The Percentage Of (e.g 200): ");
               String rnumber = bufRead.readLine();


               int repercent = Integer.parseInt(rpercent);
               int number = Integer.parseInt(rnumber);
               int percent = repercent / 100;

               int awnswer = number * percent ;

               System.out.println("Percent is: " + percent);
               System.out.println("Awnswer is: " + awnswer);
          }
          catch (IOException err) {
               System.out.println("Error reading line");
          }
          catch(NumberFormatException err) {
               System.out.println("Error Converting Number");
          }         
     }
}

Answer 1

你的问题出在这里:

       int repercent = Integer.parseInt(rpercent);
       int number = Integer.parseInt(rnumber);
       int percent = repercent / 100;

整数除法的结果最终将是一个整数，因此，例如，如果计算结果为 0.2，它将更改为 0。

这样做应该可以解决这个问题:

   double repercent = Double.parseDouble(rpercent);
   double number = Double.parseDouble(rnumber);
   double percent = repercent / 100.0;