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());
 }
}

score 1 · Answer 1 · answered Dec 29 '14 at 06:35

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;

score 0 · Answer 2 · answered Dec 29 '14 at 06:36

setQuantity method is doing an invalid check. Change if(count > 0) to if(count < 0). Even after this change, it should not work, since you are not using the set methods at all. You can probably do this while initializing the variables in the constructor,

public Invoice(String number, String partDescription, int quantity, double price)
{



    this.partNumber = number;
    this.partDescription = partDescription;
    **setQuantity(quantity);
    setPrice(price);**




}

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

2 Answers2