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Thread: How to stop a while loop thats reading text files

  1. #1
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    Default How to stop a while loop thats reading text files

    I have a program that searches through text files for whatever the user wants, if the program cant find i want it to stop and say "Student not found. Please try again.".

    Currently Ive been trying to use boolean, but when it prints it does it multiple times and i only want one line

    import java.nio.file.*;
    import java.io.*;
    import java.util.Scanner;
     
    public class SearchStudentFiles
    {
        public static void main(String[] args)
        {
     
            String studentSearch ="";
            while (!"999".equals(studentSearch))                             
            {
            File file = new File("/Users/Graham/NetBeansProjects/StudentSort/HonorsStudentList.txt");                    //PATH WILL BE DIFFERENT 
            File file2 = new File("/Users/Graham/NetBeansProjects/StudentSort/GoodStandingStudentList.txt");             //PATH WILL BE DIFFERENT
            File file3 = new File("/Users/Graham/NetBeansProjects/StudentSort/ProbationStudentList.txt");                //PATH WILL BE DIFFERENT
            Scanner scan = new Scanner(System.in);
     
            System.out.println("Enter student's First name, Last name, or Student ID Number to SEARCH: ");
            studentSearch = scan.next();
     
            Scanner scanner;
     
     
     
            //Honors Students File Search
            try
            {
              scanner = new Scanner(file).useDelimiter(",");
              boolean found = false;
              while (scanner.hasNext())
              {
                  final String lineFromFile = scanner.nextLine();
                  if (lineFromFile.contains(studentSearch))
                  {
                      Student student = new Student();
                      String[] fieldArray =  new String[3];
                      String delimiter = ",";
                      fieldArray = lineFromFile.split(delimiter);
                      student.setStudentId(Integer.parseInt(fieldArray[0]));
                      student.setLastName(fieldArray[1]);
                      student.setFirstName(fieldArray[2]);
                      student.setGradePoint(Double.parseDouble(fieldArray[3]));
     
                      System.out.printf("%-15s%-15s%13s\n", "Student ID", "Name (First Last)",  "GPA");
                      System.out.printf("%-15s%-12s%-10s%8.1f%25s\n", 
                                        student.getStudentId(), 
                                        student.getFirstName(),
                                        student.getLastName(),
                                        student.getGradePoint(),
                                        "Honor Student"); 
                      found = true;
                      break;
     
                  }
                  if(!found){
                      System.out.println("Student not found. Please try again.");
                  }
     
              }
            }
            catch (IOException e)
            {
                System.out.println(" SOMETHING WENT WRONG " + file.toString());
            }
     
     
     
     
            //Students in Good Standing File Search
            try
            {
              scanner = new Scanner(file2).useDelimiter(",");
              boolean found = false;
              while (scanner.hasNext())
              {
                  final String lineFromFile = scanner.nextLine();
                  if (lineFromFile.contains(studentSearch))
                  {
                      Student student = new Student();
                      String[] fieldArray =  new String[3];
                      String delimiter = ",";
                      fieldArray = lineFromFile.split(delimiter);
                      student.setStudentId(Integer.parseInt(fieldArray[0]));
                      student.setLastName(fieldArray[1]);
                      student.setFirstName(fieldArray[2]);
                      student.setGradePoint(Double.parseDouble(fieldArray[3]));
     
                      System.out.printf("%-15s%-15s%13s\n", "Student ID", "Name (First Last)",  "GPA");
                      System.out.printf("%-15s%-12s%-10s%8.1f%25s\n", 
                                        student.getStudentId(), 
                                        student.getFirstName(),
                                        student.getLastName(),
                                        student.getGradePoint(),
                                        "Good Standing Student");
                      found = true;
                      break;
     
                  }
                  if(!found){
                      System.out.println("Student not found. Please try again.");
                  }
     
              }
            }
            catch (IOException e)
            {
                System.out.println(" SOMETHING WENT WRONG " + file.toString());
            }
     
     
     
     
            //Probation Student File Search
            try
            {
              scanner = new Scanner(file3).useDelimiter(",");
              boolean found = false;
              while (scanner.hasNext())
              {
                  final String lineFromFile = scanner.nextLine();
                  if (lineFromFile.contains(studentSearch))
                  {
                      Student student = new Student();
                      String[] fieldArray =  new String[3];
                      String delimiter = ",";
                      fieldArray = lineFromFile.split(delimiter);
                      student.setStudentId(Integer.parseInt(fieldArray[0]));
                      student.setLastName(fieldArray[1]);
                      student.setFirstName(fieldArray[2]);
                      student.setGradePoint(Double.parseDouble(fieldArray[3]));
     
                      System.out.printf("%-15s%-15s%13s\n", "Student ID", "Name (First Last)",  "GPA");
                      System.out.printf("%-15s%-12s%-10s%8.1f%25s\n", 
                                        student.getStudentId(), 
                                        student.getFirstName(),
                                        student.getLastName(),
                                        student.getGradePoint(),
                                        "Probation Student"); 
                      found = true;
                      break;
     
                  }
                  if(!found){
                      System.out.println("Student not found. Please try again.");
                  }
     
     
              }
     
            }
            catch (IOException e)
            {
                System.out.println(" SOMETHING WENT WRONG " + file.toString());
            } 
        }
     
        }   
    }



    What am i doing wrong?

  2. #2
    Super Moderator Norm's Avatar
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    Default Re: How to stop a while loop thats reading text files

    Please copy the contents of the console from when the program executes that shows the problem.
    Add a comment like: (<<< HERE ...) where the program is not doing what is desired.

    What am i doing wrong?
    Are you printing the Not Found for every record that is read?
    When should the Not Found message be printed? Should it be after all the records are read from the file, not after each one.
    If you don't understand my answer, don't ignore it, ask a question.

  3. #3
    Junior Member
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    Default Re: How to stop a while loop thats reading text files

    Enter student's First name, Last name, or Student ID Number to SEARCH:
    232
    Student not found. Please try again.
    Student not found. Please try again.<<Here
    Student not found. Please try again.<<Here
    Student not found. Please try again.<<Here




    I want it to go through all of the text and then if it finds nothing print a single line saying "Student not found"

  4. #4
    Super Moderator Norm's Avatar
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    Default Re: How to stop a while loop thats reading text files

    go through all of the text
    When will that be true? That is where the test for found should be made and the message should be printed.
    If you don't understand my answer, don't ignore it, ask a question.

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