Question

JAVA

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

//creating class Pen
public class Pen {
   //creating private instance variable
private float price;
private String color;
//creating constructor with two fields
public Pen(float price, String color) {
   //if price is negative then it throw IllegalArgumentException
   if(price<0)
   {
       throw new IllegalArgumentException("Erorr :price can not be negative");
   }
   else {
       this.price = price;
   }
  
   this.color = color;
}
//genrating getters and setters methods
public float getPrice() {
   return price;
}
public void setPrice(float price) {
   //if price is negative then it throw IllegalArgumentException
   if(price<0)
   {
       throw new IllegalArgumentException("Erorr :price can not be negative");
   }
}
public String getColor() {
   return color;
}
public void setColor(String color) {
   this.color = color;
}
//tostring method for printing the object data
public String toString() {
   return "Pen [price=" + price + ", color=" + color + "]";
}
//main method for execution
public static void main(String[] args) {
   //creating object of class Pen
   Pen pen=new Pen(-1,"blue");//this line throw exception
   Pen pen1=new Pen(22, "Red");//this will executed
   System.out.println(pen);
   System.out.println(pen1);
}

}
Output-

terminated> Pen [Java Application] C:\Program Files\Java\jre 1.8.O_251\bin\javaw.exe (Oct 15, 2020, 12:58:10 AM – 12:58:12 AM) Exception in thread "main" java.lang.IllegalArgumentException: Erorr :price can not be negative at cegg. Pen.<init>(Pen.java:13) at cegg.Pen.main(Pen.java:45)