Java program DriverLicence using files

Question

Hi I am stuck with this particular question. I create a program called DriverExam which reads from user and match it to array and gets the answer but I want to read from files instead of array. so far I am able to read first line. can someone help me how to read all line and store in the appropriate class and get the output on no of people passed, failed and how many got correct and how many get more than 10 questions correct.

This is my code so far

The files have input something like this

B D A A C A B A C D B C D A D C C B D A

B D A A C A B A C D B C D A D C C B D A

A B D C A D C D A B A D C A B C D A B A

A B D C A D C D A B A D C A B C D A B A

public class DriversLicenceExam {

    private char[] key = { 'B', 'D', 'A', 'A', 'C', 'A', 'B', 'A', 'C', 'D',
                            'B', 'C', 'D', 'A', 'D', 'C', 'C', 'B', 'D', 'A' };


    private char[] answers;

    public DriversLicenceExam(char[] answers) {
        this.answers = answers;
    }
    public boolean passed(){

        return(totalCorrect()>=15);
    }
    public int totalCorrect(){
        int correct = 0;
        for(int i = 0; i<key.length;i++){

            if(key[i]==answers[i]){
                correct++;
            }
        }
        return correct;
    }

    public int totalIncorrect(){
        int incorrect = 0;
        incorrect = key.length - totalCorrect();
        return incorrect;
    }

    public int questionMissed(){

        int size = key.length - totalCorrect();
        int[] missed = null;
        if(size<1)
        return size;
        else
            missed = new int[size];

        int pos=0;
        for(int i = 0; i<key.length;i++){
            if(key[i]!=answers[i]){
                missed[pos] = (i+1);
                pos+=1;
            }
        }
        return size;
    }



}


      import java.io.File;
import java.io.IOException;
import java.util.Scanner;

public class DriverLicenceFilesDemo {

public static void main(String[] args) throws IOException {
    // create scanner object for keyboard input
    Scanner kb = new Scanner(System.in);

    String fileName;
    File myfile;

    char[] answers = new char[20];

    do {
        System.out.print("Please enter the name of the file: ");
        fileName = kb.next();

        myfile = new File(fileName);

        if (myfile.exists()) {
            Scanner infile = new Scanner(myfile);
            while (infile.hasNext()) {

                for (int i = 0; i < answers.length; i++) {

                    answers[i] = infile.next().charAt(0);

                }

            }
            infile.close();
        }

        else {
            System.out.println("File does not exist...");
        }

    } while (!myfile.exists());

    // create driver class
    DriversLicenceExam myDriver = new DriversLicenceExam(answers);

    // Display here
    System.out.println();
    //System.out.print("You " + (myDriver.passed() ? "passed" : "did not passed" ) + ".\n");
    System.out.println("Total correct: " + myDriver.totalCorrect());
    System.out.println("Total incorrect: " + myDriver.totalIncorrect());
    if (myDriver.passed() == true)
    {
        System.out.println("Congratulations! You have passed!");
    }
    else 
    {
        System.out.println("You have failed.");
    }
}

}

Answer 1

This will most likely be of use to you: How to read a large text file line by line using Java?

BufferedReader br = new BufferedReader(new FileReader("input_file_path"));
String line;
while ((line = br.readLine()) != null) {
   // Process the string into whatever format you need
}
br.close();

Answer 2

You probably need a String to char[] array conversion.

char[] answerArray = line.toCharArray();

Remove blank array elements and proceed with your comparison logic.

=================================================================================================

There is lot of scope for design improvement in your code. Use object oriented concepts instead of primitive datatypes etc. but anyways here is the answer for your existing code:

if (myfile.exists()) {

        BufferedReader infile = new BufferedReader(new FileReader(fileName));
        String line;
        while((line = infile.readLine()) != null){
            line = line.replaceAll("\\s", ""); // remove all blank spaces.
            if(!line.equals("")){
                answers = line.toCharArray();

            // create driver class
            DriversLicenceExam myDriver = new DriversLicenceExam(answers);

            // Display here
            System.out.println();
            //System.out.print("You " + (myDriver.passed() ? "passed" : "did not passed" ) + ".\n");
            System.out.println("Total correct: " + myDriver.totalCorrect());
            System.out.println("Total incorrect: " + myDriver.totalIncorrect());
            if (myDriver.passed() == true)
            {
                System.out.println("Congratulations! You have passed!");
            }
            else 
            {
                System.out.println("You have failed.");
            }
            System.out.println("============================================================");
            }
        }
        infile.close();
    }

    else {
        System.out.println("File does not exist...");
    }