Question

i need this done in java

plz, add comments for every single method. also, make as simple as possible.

3. Write a GUI for computing the statistics of numbers input from the user. The GUI should have a text field and a button for adding floating point numbers. Each time a number is entered have a label show the current max, min and average. Have your GUI accept numbers whether the button is pressed or the enter key is pressed in the data field. 4. Write a GUI with three text fields, one for the initial amount of a savings account, the annual interest rate and a number of years. Add a button "Calculate" and a read-only text area to display the balance per year. Show both the balance and the year in a format similar to: Initial amount: $50.00 After year 1: $51.00 After year 2: $52.00 (Extra) Your GUI should really show an error (JOptionPane?) if any of the fields are negative or are invalid data types like strings

Answer 1

3. CODE:

import javax.swing.*;

import java.awt.*;

import java.awt.event.*;

import java.util.*;

class StatsFrame extends JFrame implements ActionListener {

private JTextField tfNumber = new JTextField(10);

private JButton btnAdd = new JButton("ADD"); // creates the add button

private JLabel lblMax = new JLabel(); // creates label for maximum

private JLabel lblMin = new JLabel(); // creates label for minimum

private JLabel lblAvg = new JLabel(); // creates label for average

ArrayList<Double> numbers = new ArrayList<Double>();

public StatsFrame() {

setLayout(new FlowLayout()); // sets the new FlowLayout

setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); // set the default operation upon close

setSize(200,500); // sets the size

setVisible(true); // sets the JFrame visible

add(tfNumber);

add(btnAdd);

btnAdd.addActionListener(this);

add(lblMax);

add(lblMin);

add(lblAvg);

}

//the button click event

public void actionPerformed(ActionEvent e) {

try{

double inputNum = Double.parseDouble(tfNumber.getText());// get the input number

numbers.add(inputNum);//add the number to the arraylist

}

catch(NumberFormatException ex) {

// an error message to be displayed upon numberformat exception occurs

JOptionPane.showMessageDialog(this, "Invalid Input", "Error", JOptionPane.ERROR_MESSAGE);

}

double max = Collections.max(numbers);// get the maximum of numbers from the arraylist

double min = Collections.min(numbers);// get the minimum of numbers from the arraylist

double sum = 0;// a variable that holds the sum of the arraylist

for (int i = 0; i < numbers.size() ;i++ ) {

sum += numbers.get(i);

}

double avg = sum/numbers.size();

//setting the text for appropriate labels

lblMax.setText("Current Max = " + String.valueOf(max));

lblMin.setText("Current Min = " + String.valueOf(min));

lblAvg.setText("Current Avg. = " + String.valueOf(avg));

}

}

//driver code

public class NumberStats{

public static void main(String[] args) {

StatsFrame sf = new StatsFrame();

}

}

OUTPUT:

4. CODE:

import javax.swing.*;

import java.awt.*;

import java.awt.event.*;

// the jframe with all the fields necessary for calculating the balance every year

class BalanceFrame extends JFrame implements ActionListener {

private JLabel lblInAmt = new JLabel("Enter initial balance:");// a label for a prompt to input initial balance

private JLabel lblInterestRate = new JLabel("Enter Interest rate:");// a label for a prompt to input interest rate

private JLabel lblYears = new JLabel("Enter no of Years:");// a label for a prompt to input no. of years

private JTextField tfInAmt = new JTextField(10);// a textfield to get initial amount

private JTextField tfInterestRate = new JTextField(10);// a textfield to get interest rate

private JTextField tfYears = new JTextField(10);// a textfield to get no. of years

private JButton btnCalculate = new JButton("Calculate"); // creates the calculate button

private JTextArea taAmount = new JTextArea(); // creates textarea for showing initial balance

private JTextArea taBalance = new JTextArea(); // creates textarea for showing balance report

public BalanceFrame() {

setLayout(new FlowLayout()); // sets the new FlowLayout

setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); // set the default operation upon close

setSize(270,500); // sets the size

setVisible(true); // sets the JFrame visible

//adding all the components to the frame

add(lblInAmt);

add(tfInAmt);

add(lblInterestRate);

add(tfInterestRate);

add(lblYears);

add(tfYears);

add(btnCalculate);

btnCalculate.addActionListener(this);

add(taAmount);

add(taBalance);

taAmount.setEditable(false);

taBalance.setEditable(false);

}

//the button click event

public void actionPerformed(ActionEvent e) {

double initialBalance = 0; double interestRate = 0 ;double noOfYears = 0;

try{

initialBalance = Double.parseDouble(tfInAmt.getText());// get the initial balance

interestRate = Double.parseDouble(tfInterestRate.getText());// get the interest rate

noOfYears = Double.parseDouble(tfYears.getText());// get the no of years

}

catch(NumberFormatException ex) {

// an error message to be displayed upon numberformat exception occurs

JOptionPane.showMessageDialog(this, "Invalid Input", "Error", JOptionPane.ERROR_MESSAGE);

System.exit(0);

}

double thisYearBalance = 0;

String balanceEachYear = "";// the string to show the balance report each year

taAmount.setText("Initial amount: $" + initialBalance);// set initial amount

for (int i = 0; i < noOfYears ;i++ ) {

thisYearBalance += initialBalance + (interestRate /100);// calculating the balance this year

balanceEachYear += "After Year: " + (i + 1) + "$" + thisYearBalance + "\n";

}

taBalance.setText(balanceEachYear); // set balance report each year in the textarea

}

}

//driver class

public class ShowBalance{

public static void main(String[] args) {

BalanceFrame bf = new BalanceFrame();

}

}

OUTPUT:

ERROR MESSAGE: