java - 使用文本中的公式/写作文本

Question

所以，我的演讲幻灯片甚至我的书都没有真正很好地解释如何使用文本文档中的公式(据我的理解)，然后当代码成功运行/编译时，它将创建一个“Results.txt”位于同一文件夹中。

这些是记事本文档中的公式。没什么疯狂的，只是一个概念证明 4*5.. 3/4... 3 - 1.. 2 + 3..

import java.io.*;
import java.util.*;

public class ReadFileLineByLine {

public static void main(String[] args) throws FileNotFoundException {
        String line;
        int numberOfLines = 3;
        String[] textData = new String[numberOfLines];

        int i;

        for(i = 0; i < numberOfLines; i++){
            textData[i] = textReader.readLine();
        }

        text.Reader.close();
        return textData;

        try {
               File inputfile = new File(args[0]); //new File("formulas.txt")
               Scanner input = new Scanner(new File("C:\Users\Frost\Documents\Question4"));
               BuffredReader br = new BufferedReader(new FileReader("C:\Users\Frost\Documents\Question4"));
               PrintWriter output = new PrintWriter("Results.txt");           



while (input.hasNextLine()) {
      line = input.nextLine();

      System.out.println("read <" + line + ">"); // Display message to commandline             
      // Declare ArrayList of for storing tokenized formula from String line                                       

double result = 0; // The variable to store result of the operation 

   // Determine the operator and calculate value of the result 
    System.out.println(formula.get(0) + ' ' + formula.get(1) + ' ' + 
     formula.get(2) + " = " + result); // Display result to command line 

// Write result to file           
}           
// Need to close input and output files       
} 

catch (FileNotFoundException e) {            
   System.out.println("Error reading file named " + Formulas.txt);

     }   


  }  
}

Answer 1

这里有一些可以帮助您入门的东西。 //TODO: 注释是您需要构建逻辑的地方。请务必将文件路径更改回您需要的路径。我将它们更改为临时位置。还要更改打印的消息，因为我只是将一些东西放在那里作为概念证明。我试图彻底发表评论，但请毫不犹豫地提出问题。

import java.io.*;
import java.util.*;

public class ReadFileLineByLine {

public static void main(String[] args) throws FileNotFoundException {
    String line = "";
    //Declare Scanner and PrintWriter outside of try clause so they can be closed in finally clause
    Scanner input = null;
    PrintWriter output = null;

    try {
        //Instantiate input and output file
        input = new Scanner(new File("C:\\Temp\\test.txt"));
        output = new PrintWriter(new File("C:\\Temp\\Results.txt"));

        //Loop through lines in input file
        while (input.hasNextLine()) {
            line = input.nextLine();

            // Display message to commandline
            System.out.println("read <" + line + ">"); 

            // Populate ArrayList of tokenized formula from String line
            //TODO:

            // The variable to store result of the operation
            double result = 0; 

            // Determine the operator and calculate value of the result
            //TODO:

            // Write result to file
            output.println("Print result of " + line + " to Results.txt");
        }
    } catch (FileNotFoundException e) {
        //Exception thrown, print message to console
        System.out.println("File Not Found: " + e.getMessage());
    } finally {
        //close files in finally clause so it happens even if exception is thrown
        //I also set to null as extra precaution
        input.close();
        input = null;
        output.close();
        output = null;
    }
}
}