有时输出数字不正确。 [英] Output of numbers are incorrect sometimes.

问题描述

这是我的任务，给定一个表达式的输入，该表达式包含一串字母和运算符（加号，减号和字母.IE：'b-d + e-f'）和一个带有集合的文件由逗号分隔的变量/值对（即：a = 1，b = 7，c = 3，d = 14）写入将输出输入表达式的结果的程序。
例如，如果表达式输入为（a + b + c -d）且文件输入为（a = 1，b = 7，c = 3，d = 14），则输出为 - 3。
您好我正在尝试做一个简单的java代码，如果我添加4个字母则输出一个数字。当我做不同的组合，比如d-c + a + b时，它会给我一个像118.0这样的内含号。有人能告诉我在我的代码中我的计算错误..

This is my task, Given an input of an expression consisting of a string of letters and operators (plus sign, minus sign, and letters. IE: ‘b-d+e-f’) and a file with a set of variable/value pairs separated by commas (i.e: a=1,b=7,c=3,d=14) write a program that would output the result of the inputted expression. For example, if the expression input was ("a + b+c -d") and the file input was ( a=1,b=7,c=3,d=14) the output would be -3. Hi I am trying to do a simple java code which outputs a number if i add 4 letters. When I do different combinations like d-c+a+b it gives me a inccorect number like 118.0. Can someone tell me where in my code my calculations are wrong..

谢谢

ValVarPairs.txt包含这些数字 - > a = 100，b = 5，c = 10，d = 13

the ValVarPairs.txt contains these numbers-> a=100,b=5,c=10,d=13

这就是我编码的内容。

This is what i coded.

    package com.ecsgrid;

import java.io.*;

public class testC {

public static void main(String[] args) {
  int i = 0,j = 0;
  double result, values[] = new double[4];
  char k, operators[] = new char[3];
  for (i = 0; i <= 2; i++) 
    operators[i] = '+';      // default is to add the values

  File myfile;
  StreamTokenizer tok;
  BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
  String InputText;

  i = 0;
  try {
    myfile = new File("C:\\VarValPairs.txt");
    tok = new StreamTokenizer(new FileReader(myfile));  
    tok.eolIsSignificant(false);

    while ((tok.nextToken() != StreamTokenizer.TT_EOF) && (i <= 3)){
      if ((tok.ttype == StreamTokenizer.TT_NUMBER))
        values[i++] = tok.nval;
      }
  }
  catch(FileNotFoundException e) { System.err.println(e);  return; }
  catch(IOException f) { System.out.println(f); return; }

  System.out.println("Enter letters and operators:");

  try {
    InputText = in.readLine(); 
  }  
  catch(IOException f) { System.out.println(f); return; }

  for (i = 0; i < InputText.length(); i++)
  {
     k = InputText.charAt(i);
     if ((k == '+') || (k == '-'))
     {
        if (j <= 2) operators[j++] = k;   
     }
  } 

  result = values[0];
  for (i = 0; i <= 2; i++){
   if (operators[i] == '+')
     result = result + values[i+1];  
   else
     result = result - values[i+1];
  }
  System.out.println(result);  
 }
}

推荐答案

我我不确定你的计算错误，但你可以这样做：

I'm not sure where your calculations are wrong, but you could do something like this:

编辑代码：

    import java.io.*;
    import java.util.*;
    public class test{
        public static int a;
        public static int b;
        public static int c;
        public static int d;
        public static int fin = 0;
        public static String temp;
        public static void main(String[] args){
        try{
            Scanner input = new Scanner(new File("yourfile.txt"));
            temp = "";
            while(input.hasNext()){ //stores the letters
                temp = temp + input.next();   
            }
            input.close();
        }
        catch(Exception e){

        }
            /*
            THIS IS IF THE FILE yourfile.txt IS IN THIS FORMAT EXACTLY:
            a=1
            b=2
            c=3
            d=4
            */
            for(int i = 0; i < temp.length(); i++){ //intitializes the values
                String message = "" + temp.charAt(i);
                if(message.equals("a") || message.equals("b") || message.equals("c") || message.equals("d")){
                    String val = "" + temp.charAt(i+2);
                    setValue(message,val);
                }
            }
            Scanner enter = new Scanner(System.in);
            System.out.print("ENTER EXPRESSION: ");
            String ex = enter.nextLine();
            for(int b = 0; b < ex.length(); b++){
                String m = ""+ ex.charAt(b);
                if(b == 0){
                    if(m.equals("a") || m.equals("b") || m.equals("c") || m.equals("d")){
                        fin = fin + getValue(m);   
                    }
                }
                else{
                if(m.equals("a") || m.equals("b") || m.equals("c") || m.equals("d")){
                   String check = "" + ex.charAt(b-1);
                   if(check.equals("+")){
                        fin = fin + getValue(m);  
                    }
                    if(check.equals("-")){
                        fin = fin - getValue(m); 
                    }
                }
                }
            }
            System.out.println(fin);
        }
        public static void setValue(String variable, String value){
            if(variable.equals("a")){
                a = Integer.parseInt(value);   
            }
            if(variable.equals("b")){
                b = Integer.parseInt(value);   
            }
            if(variable.equals("c")){
                c = Integer.parseInt(value);   
            }
            if(variable.equals("d")){
                d = Integer.parseInt(value);   
            }
        }
        public static int ret = 0;
        public static int getValue(String var){
           if(var.equals("a")){
                ret = a; 
            }
            if(var.equals("b")){
                ret = b;
            }
            if(var.equals("c")){
                ret = c;  
            }
            if(var.equals("d")){
                ret = d;   
            }
            return ret;
        }
    }

您的代码中存在一些问题，您使用==而不是 .equals（）

There are some problems in your code where you use "==" instead of .equals()

这篇关于有时输出数字不正确。的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！