CODEWITHSUNDEEP
java
user3341694
user3341694

Reputation: 1

Java: If statement

I am trying to add another error for the if (student == 1,2,3).
And if they input a 0 for the amount of credits they are taking it shows an invalid input message.

Any help on what I am doing wrong?

import javax.swing.*;
import java.text.*;

public class TuitionCost {

  public static void main(String[] args) {
    int costHours;
    int student;
    String input;
    double a;
    double b;
    double c;
    DecimalFormat dollar = new DecimalFormat("#,##0.00");

    JOptionPane.showMessageDialog(null, "OCC Tuition Cost Calculation Program", "Tuition Costs at OCC", JOptionPane.INFORMATION_MESSAGE);
    input = JOptionPane.showInputDialog(null, "Are you a:\n1 - College District Residents\n2 - Non-Residents of College District\n3 - Out-of-State and International Students\n\nPlease enter 1, 2 or 3:", "Input", JOptionPane.QUESTION_MESSAGE);
    student = Integer.parseInt(input);

    if (student == 1) {
      input = JOptionPane.showInputDialog(null, "How many credit hours are you taking?", JOptionPane.QUESTION_MESSAGE);
      costHours = Integer.parseInt(input);
      a = costHours * 76.40;
      JOptionPane.showMessageDialog(null, dollar.format(costHours) + " hours at $76.40 per hour yields a tuition of $" + dollar.format(a));
      System.exit(0);
    }

    if (student == 2) {
      input = JOptionPane.showInputDialog(null, "How many credit hours are you taking?", JOptionPane.QUESTION_MESSAGE);
      costHours = Integer.parseInt(input);
      b = costHours * 139.10;
      JOptionPane.showMessageDialog(null, dollar.format(costHours) + " hours at $139.10 per hour yields a tuition of $" + dollar.format(b));
      System.exit(0);
    }

    if (student == 3) {
      input = JOptionPane.showInputDialog(null, "How many credit hours are you taking?", JOptionPane.QUESTION_MESSAGE);
      costHours = Integer.parseInt(input);
      c = costHours * 195.15;
      JOptionPane.showMessageDialog(null, dollar.format(costHours) + " hours at $195.15 per hour yields a tuition of $" + dollar.format(c));
      System.exit(0);
    } else {
      JOptionPane.showMessageDialog(null, "You must enter a 1, 2, or 3.\nPlease Run the program again.", "Invalid Input", JOptionPane.ERROR_MESSAGE);
    }
    System.exit(0);
  }
}

Upvotes: 0

Views: 564

Answers (6)

Kevin Bowersox
Kevin Bowersox

Reputation: 94429

I would recommend following the DRY principle for this code. Declare the rates as a double[] (although Double is not recommended for money) and then use the array to get the values for each particular type of student. The code for each student is so similar that a simple array will allow the main logic to be wrote once.

double[] rates = {76.40,139.10,195.15};
student = Integer.parseInt(input);

if(student > 0 && student < 4){
    input = JOptionPane.showInputDialog(null, "How many credit hours are you taking?", JOptionPane.QUESTION_MESSAGE);
    costHours = Integer.parseInt(input);
    if(costHours != 0){
        a = costHours * rates[student];
        JOptionPane.showMessageDialog(null, dollar.format(costHours) + " hours at $" + rates[student] + " per hour yields a tuition of $" + dollar.format(a));
    }else{
        JOptionPane.showMessageDialog(null, "Credit hours cannot be zero.", "Invalid Input", JOptionPane.ERROR_MESSAGE);
    }
    System.exit(0);
}else{
    JOptionPane.showMessageDialog(null, "You must enter a 1, 2, or 3.\nPlease Run the program again.", "Invalid Input", JOptionPane.ERROR_MESSAGE);
}

Gist of Full File

Upvotes: 2

ErstwhileIII
ErstwhileIII

Reputation: 4843

You might want to simplify your processing and factor your code into several methods. Consider the following organization:

  1. Put the hourly cost depending on student residence into an array
  2. Create a method to show a message
  3. Create a method to ask a question, get an int response AND check that the response is between min and max

Then you can adjust your code to be a bit more simple -- for example.

package com.snippet;

import java.text.DecimalFormat;
import javax.swing.JOptionPane;

public class TuitionCostNew {
private static TuitionCostNew me;

/** cost per hour for:
 *  college district resident, 
 *  in-state but not college district, 
 *  out of state (including international)
 * 
 */
private static double[] hourCost = { 76.40, 139.10, 195.15 };

/**
 * @param args
 */
public static void main(String[] args) {
    // TODO Auto-generated method stub
    me = new TuitionCostNew();
    me.start(hourCost);
}

/**
 * @param hourCost
 */
private void start(double[] hourCost) {
    int studentType;
    int creditHours;
    double tuitionCost;
    DecimalFormat dollar = new DecimalFormat("#,##0.00");

    showInformationMessage("OCC Tuition Cost Calculation Program","Tuition Costs at OCC");

    studentType = inputIntegerDialog(
            "Are you a:\n1 - College District Residents\n2 - Non-Residents of College District\n3 - Out-of-State and International Students\n\nPlease enter 1, 2 or 3:",
            1, 3);

    creditHours = inputIntegerDialog("How many credit hours are you taking?", 1, 25);
    tuitionCost = hourCost[studentType-1] * creditHours;
    showMessage(dollar.format(creditHours) + " hours at "
            + hourCost[studentType-1] + " per hour yields a tuition of $"
            + dollar.format(tuitionCost));
}

/** Show user an informational message pane, including a title for the pane and a message.
 * @param title
 * @param message
 */
private void showInformationMessage(String title, String message) {
    // TODO Auto-generated method stub
    JOptionPane.showMessageDialog(null, title, message,
            JOptionPane.INFORMATION_MESSAGE);
}

/** Shoe user a simple message
 * @param message
 */
private void showMessage(String message) {
    JOptionPane.showMessageDialog(null, message);
}

/** Ask the user to enter an integer value using the message, where the value must be between min and max
 * @param message
 * @param min
 * @param max
 * @return
 */
private int inputIntegerDialog(String message, int min, int max) {
    String input;
    int value = -1;
    boolean validAnswer = false;

    while (!validAnswer) {
        input = JOptionPane.showInputDialog(null, message, "Input",
                JOptionPane.QUESTION_MESSAGE);
        value = Integer.parseInt(input);
        validAnswer = value >= min && value <= max;
        if (!validAnswer) {
            String errMessage = "Invalid entry. Enter number between "
                    + min + " and " + max + ". Try again.";
            showMessage(errMessage);
        }
    }
    return value;
}

}

Upvotes: 1

nikis
nikis

Reputation: 11234

It's better to use switch if you have a set of possible values:

switch (student) {
    case 0:
        //do stuff
        break;
    case 1:
        //do stuff
        break;
    ...
    default:
        //it's analog of else
        //do stuff
        break;
}

http://docs.oracle.com/javase/tutorial/java/nutsandbolts/switch.html

Upvotes: 2

korhner
korhner

Reputation: 733

This is the proper way to write if-else if-else statements. You are missing "else".

if (student == 1)
{

}
else if (student == 2)
{

}
else if (student == 3)
{

}
else
{

}

Upvotes: 4

ltalhouarne
ltalhouarne

Reputation: 4636

That's because else will catch a value that is different from 1, 2 or 3:

else               
     JOptionPane.showMessageDialog(null, "You must enter a 1, 2, or 3.\nPlease Run the program again.", "Invalid Input", JOptionPane.ERROR_MESSAGE);
     System.exit(0);

You need to add a condition to check for 0:

if (student == 0){}

and use else-if syntax:

if(student==0){
}else if(student==1){
}else if(student==2){
}else if(student==0){
}else{
//anything else
}

Upvotes: 0

Paul Hicks
Paul Hicks

Reputation: 13999

You're missing the "else" between all the ifs. So you're getting this flow:

if (1) { ... }
and if (2) { ... }
and if (3) { ... } else { ... }

You want "or" logic everywhere.

Upvotes: 0

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