CODEWITHSUNDEEP
javaarraysparallel-arrays
noSpaces
noSpaces

Reputation: 1

How can I access the full contents of a parallel array in java?

I am trying access the full contents of a parallel array by having the user enter an identification number. The array only seems to return results for the first four items [0-3]. The remainder are returned as not found. Using Eclipse, I tried to fully dimension the array to 10 memory locations, however, I get errors.

import java.util.*;
import javax.swing.JOptionPane;

public class StudentIDArray {
    static String[] studentNum = new String[]
            {"1234", "2345", "3456", "4567", "5678", "6789", "7890", "8901", "9012", "0123"};
    static String[] studentName = new String[]
            {"Peter", "Brian", "Stewie", "Lois", "Chris", "Meg", "Glen", "Joe", "Cleveland", "Morty"};
    static double[] studentGpa = new double[]
            {2.0, 3.25, 4.0, 3.6, 2.26, 3.20, 3.45, 3.8, 3.0, 3.33};

    public static void main(String[] args) {
        String studentId = null;
        while ((studentId = JOptionPane.showInputDialog(null, "Please enter your Student ID number to view your name and GPA")) != null) {
            boolean correct = false;
            for (int x = 0; x < studentId.length(); ++x) {
                if (studentId.equals(studentNum[x])) {
                    JOptionPane.showMessageDialog(null, "Your name is: " + studentName[x] + "\n" + "Your GPA: " + studentGpa[x], "GPA Results", JOptionPane.INFORMATION_MESSAGE);
                    correct = true;
                    break;
                }
            }
            if (!correct) {
                JOptionPane.showMessageDialog(null, "Student ID not found, try again.", "Not found", JOptionPane.INFORMATION_MESSAGE);
            }
        }
    }
}

Upvotes: 0

Views: 490

Answers (3)

WonderWorld
WonderWorld

Reputation: 966

In the for loop change:

studentId.length();

to

studentNum.length;

You are now using the length of the input string while you need to the length of the array.

Upvotes: 4

Tom
Tom

Reputation: 17587

Please look at your for loop:

for (int x = 0; x < studentId.length(); ++x)

Instead of using the length of your studentNum array, you're using the length of the user input studentId which is most likely 4 characters long (due to your given student ids in studentNum). That is why your program only find entries on index 0 - 3 (The array only seems to return results for the first four items [0-3]).

Change it to

for (int x = 0; x < studentNum.length; ++x)

to fix it.

Upvotes: 2

amahfouz
amahfouz

Reputation: 2398

Shouldn't you be iterating over the "studenNum" array in your for loop? You have a typo/bug where you are iterating over the wrong variable.

Upvotes: 3

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