Question

Write a class called Pen that contains the following information:

1. Private instance variables for the price of the pen (float) and color of the pen (String).
2. A two-argument constructor to set each of the instance variables above. If the price is negative, throw an IllegalArgumentException stating the argument that is not correct.

3. Get and Set methods for each instance variable with the same error detection as the constructor.

public class Pen {

Answer 1

Here is the solution,

// your code starts here
import java.util.Scanner;

public class Pen
{
// instance variables - replace the example below with your own
private float price;
private String color;
  

// constructor with two arguments/parameters
public Pen(float price , String color)
{
try {
if(price < 0)
throw new IllegalArgumentException("Price cannot be negative");
this.price = price;
this.color = color;
}
catch(IllegalArgumentException e) {
System.out.println(e);
}
}
  
// for getting price
// no need for exception since we will never allow negative number
// for the object
public float getPrice()
{
return this.price;
}
  
  
// for getting color
// exception handling is not for color
public float getColor()
{
return this.price;
}
  
  
// setting price, over here we again have to check for negative numbers
// so we have the Exceptional handling (IllegalArgumentException)
public void setPrice(float price)
{
try {
if(price < 0)
throw new IllegalArgumentException("Price cannot be negative");

this.price = price;
  
}
catch(IllegalArgumentException e) {
System.out.println(e);
}

}
  
  
// to set color. No exception handling to be done for color.
public void setColor(String color)
{   
this.color = color;
}
  
  
// main/driver
public static void main(String[] args) {
// trying to create object with negative number
// exception will be thrown here
Pen a = new Pen(-2,"blue");
// creating object
Pen b = new Pen(2,"black");
// trying to set value with negative number
// exception will be thrown here
b.setPrice(-9);
}
}
//code ends here

here is the sample output:-

hhere is the screenshot of the code for proper understanding.

Thank You.