java - 读取文件并打印字符串和整数的平均值

Question

例如，我有一个文本文件，每行包含一个名称和一个整数序列

Jules 50 60 40
Ali 45 70 70 90
Emma 45 54

我的代码有这个，但它不会打印出平均值，我也不确定如何读取整数序列

   public void AverageMarks(String fName, String pname) {

    BufferedReader br = null;
    try{ 
         br = new BufferedReader(new FileReader(fName));
        }catch(FileNotFoundException e){
        System.out.println("Could not find file");
    }

    try{    
        double average = 0;
        double sum = 0;
        String line;

        while((line = br.readLine()) != null){
          String[] lines = line.split(" ");

           if(pname.equals(lines[0])){
                for(int i =0; i<lines.length; i++){
              sum+= Double.parseDouble(lines[i+1]);
            } 
             average = sum / lines.length;
            System.out.println(average);
            System.exit(0);
          }
          else{
              System.out.println(pname + " No such name");
              System.exit(0);
            }
        }

    }catch(IOException e){
        System.out.println("An error has occured");
    }
    finally{
        System.exit(0);
    }
  }

例如平均值是双倍...

• AverageMarks("myfile.txt","Jules") 应打印 50.0
• AverageMarks("myfile.txt","Ali") 应打印 68.75
• AverageMarks("myfile.txt","Neil") 应该打印 Neil No such name

Answer 1

问题是，您的 while 循环中不应该有 else block 。 else block 语句应该不显眼，以确保您已处理文件中的所有行并且不存在此类名称。 for 循环索引也存在问题。它应该从 1 开始，而不是从 0 开始。试试这个:

public void AverageMarks(String fName, String pname) {

    BufferedReader br = null;
    try{ 
         br = new BufferedReader(new FileReader(fName));
        }catch(FileNotFoundException e){
        System.out.println("Could not find file");
    }

    try{    
        double average = 0;
        double sum = 0;
        String line;

        while((line = br.readLine()) != null){
          String[] lines = line.split(" ");

          if(pname.equals(lines[0])){
            if(lines.length > 1) { // check to calculate average only when there are numbers as well in the line
              for(int i = 1; i<lines.length; i++){ // loop index shold start from 1 as element at index 0 is name
                sum+= Double.parseDouble(lines[i]);
              }

              average = sum / (lines.length - 1);
            }
            System.out.println(average);
            System.exit(0);
          }
        }

        // moved these lines from inside loop, to make sure all the names in the files have been checked
        System.out.println(pname + " No such name");
        System.exit(0);

    }catch(IOException e){
        System.out.println("An error has occured");
    }
    finally{
        System.exit(0);
    }
  }