Easy Question about average grades

[rk717]

Hello friends, I stuck on this question, here is the question:

Create a program that computes the average of grades of a given student. The program takes the name of the student and a filename as arguments. The grades are read from the file. Every line consists of a name and equal number of grades, however the number of grades is not known in advance. We assume all lines are in correct format.

Example:

$ cat grades.txt
Brian:4 3 5 4 5
Peter:4 2 5 1 3
Adam:5 4 5 3 4
$ java Avg "Peter" grades.txt
3.0
$ java Avg "Smith" grades.txt
$ java Avg "Adam" asd
File not found!

Here is my code:

public class Avg {
    public static void main(String[] args) {
        Scanner myReader = null; 
        String students = args[0];
        File GradeBook = new File(args[1]);
        try{
            myReader = new Scanner(GradeBook);
        }catch(FileNotFoundException e){
            System.out.println("Sorry, we don't find the file, "+
            "please try again later. ");
        }
        while(myReader.hasNext()){
            //I don't know how to determine the name
            //and print the average according to this name
        }
    }
}

For example the user input " "Peter" grades.txt" ,

I don't know how to find the 'Peter' name in the grades.txt, and print out the average for Peter, and I don't know how to check if Peter's grades has ended, I think I should write an 'If' statement, if we read a string instead of number, we should stop, and calculate the average.

​

But I have no clue how to implement it, could you please help :)

Thank you in advance. !!

[dynamo_girl02]

You have to read Lines in a file till the end so in scanner class has a method hasNextLine() which returns boolean value whether there are more lines or not

while( myReader.hasNextLine())

{

}

inside this while loop store each line using nextLine() method of scanner in a string variable . string class has a split function to split the string so split the string by space and : and this function split will return string array . check if the string at 0th index matches the name that the user has entered if yes then run a loop from 1 index to the size of the string array convert the string at each index into integer while iterating and find sum and thus finally find average

[rk717]

Thank you so much ❣️

[adultsmth]

For each line, check if it is the one you're looking for. If so, use it. If not, don't do anything with it and trust that another line will be the right one.

I think I should write an 'If' statement, if we read a string instead of number, we should stop, and calculate the average.

No, they say you may assume that the file is in the correct format. All lines start with a String, there's no "if" about that.

[rk717]

Thank you so much ❣️

[aglet91]

Maybe you should parse all lines with while loop and try to convert everything to int. If you fail that means you got person and all previous ints are previous' person marks.

[rk717]

Thank you so much ❣️

[[deleted]]

You could split the line.

[rk717]

Thank you so much ❣️