Question

请原谅我这个问题是否真的很明显，但我已经尝试了一切。

我正在尝试制作一个计算数字百分比的计算器。

但是当我使用这段代码时，它会继续为输出输出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

你的问题在于：

       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，如果计算得出0.2，它将更改为0。

做这样的事情应该解决它：

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

Answer 2

int是自然数（或者是负数......等等， int是整数），它不能是0或1之间的任何数字。你必须使用如果您想查看float

之类的内容，请double或0,25

Answer 3

尝试使用float代替int

float repercent = Float.parseFloat(rpercent);
float number = Float.parseFloat(rnumber);
float percent = repercent / 100;

Answer 4

int percent = repercent / 100;无效。 Use float或double数据类型。

Answer 5

我已经清理了你的代码了。正如其他人所指出的那样，主要问题是过早整数除以100.删除了异常处理，因为它是多余的并且掩盖了默认异常处理程序打印的完整堆栈跟踪。

package test;

import static java.lang.Integer.parseInt;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Test {
  public static void main(String args[]) throws Exception {
    final BufferedReader bufRead = new BufferedReader(new InputStreamReader(System.in)) ;
    System.out.println("Hello...");
    System.out.println("Please Enter In The Percentage You Want To Find (e.g 25): ");
    final int percent = parseInt(bufRead.readLine());
    System.out.println(
        "Please Enter In The Number You Wish To Find The Percentage Of (e.g 200): ");
    final int number = parseInt(bufRead.readLine());
    final int answer = number * percent / 100; // or use a floating-point type here
    System.out.println("Percent is: " + percent);
    System.out.println("Answer is: " + answer);
  }
}

用低于零的数字计算

5 个答案: