Java Invoice program - set quantity to 0 set price to 0.0

Question

I have pretty much completed this program except when I set a price or quantity object to a negative number it does not set to 0. The directions say if the price is not a positive number it should be set to 0.0 and if the quantity is not a positive number it should be set to 0. Here are my codes can anyone tell me where I went wrong.

This exercise is 3.12 Invoice class form Deitel 10th edition How to program:

public class Invoice {  
private String partNumber;
private String partDescription;
private int quantity;
private double priceperitem;
private double amount;  
public Invoice(String number, String partDescription, int quantity, double price)
{       
        this.partNumber = number;
        this.partDescription = partDescription;
        this.quantity = quantity;
        this.priceperitem = price;
}       
public void setPartNumber(String number)
{           
        partNumber = number;            
}       
public String getPartNumber()
{           
        return partNumber;
}   
public void setPartDescription (String description)
{           
        partDescription = description;
}       
    public String getPartDescription(){         
        return partDescription;         
    }   
    public void setQuantity(int count){         
        if(count > 0)
            quantity = 0;           
    }       
    public int getQuantity(){           
        return quantity;
    }   
    public void setPrice (double price){            
        if(price > 0.0)
            priceperitem = price;           
        if(price < 0.0)
            priceperitem = 0.0; 
    }       
    public double getPrice(){           
        return priceperitem;
    }   
    public double getInvoiceAmount(){           
         amount = getQuantity() * getPrice();           
         return amount;
    }       
}

import java.util.Scanner;
public class InvoiceTest {
public static void main(String[] args) {        
    int quantity;
    double price;
    double invoiceAmount;       
    Invoice invoice1 = new Invoice("1234","Hammer",-5, -39.75);     
    Scanner keyboard = new Scanner (System.in);     
    System.out.printf( "Part number: %s\n", invoice1.getPartNumber());
    System.out.printf( "Part Description: %s\n", invoice1.getPartDescription());
    System.out.printf( "Quantity: %s\n", invoice1.getQuantity());
    System.out.printf( "Price: %s\n", invoice1.getPrice());
 }
}

Answer 1

You are checking for the condition if price<0 then set price to 0 , in you setter method , i.e in method setPrice. But you are passing -ve argument for price thorugh constructor, which has no such check. Add the check in constructor too:-

public Invoice(String number, String partDescription, int quantity, double price)
{
    this.partNumber = number;
    this.partDescription = partDescription;
    this.quantity = quantity;

    if(price > 0.0)
     priceperitem = price;

    if(price < 0.0)
     priceperitem = 0.0; 

}

Same goes for Quantity check, add check for quantity in constructor in similar way.

Also note that your condition in setQuantity is not valid change it to:-

  if(quantity > 0)
  this.quantity = price;

  if(quantity < 0)
  this.quantity = 0.0;