Thread: Working with loops for the first time.

Hello.

So far, I am in my 3rd week of Java programming and I've finally run into a bit of a problem. We were given an assignment of the following:
Scenario 1: Customer purchases all 9 items Please enter your name: Lisa Miller (This is what the sample output looked like)

GRAPEFRUIT PRODUCT
1. gPod shuffle $49
2. gPod Touch $299
3. gPad Mini $329
4. gPad 2 $399
5. gPhone $199
6. gMac $1299
7. MacNovel Pro $1199
8. MacNovel Air $999
9. MiniMac $599
10. Complete my order

Please select an item from the menu above: 5
Please select anotheritem from themenu above: 2
etc,

Thank you for ordering with Grapefruit Company, Lisa Miller
Total items ordered: 9
Price of items ordered: $5371
Sales tax: $ 349.115
Total amount due: $ 5720.115

package onlineordering;
 
import java.util.Scanner;
 
/**
 *
 * @author jamesbottom
 */
public class OnlineOrdering {
 
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
 
        //Declare variables
        final int GPOD_SHUFFLE = 49;
        final int GPOD_TOUCH = 299;
        final int GPAD_MINI = 329;
        final int GPAD_2 = 399;
        final int GPHONE = 199;
        final int GMAC = 1299;
        final int MACNOVEL_PRO = 1199;
        final int MACNOVEL_AIR = 999;
        final int MINIMAC = 599;
        int nProductNumber = 0;
        int nSum = 0;
        Scanner input = new Scanner(System.in);        
 
        //Prompt user for name
        System.out.print("Please enter your name: ");
 
        //Get/read name 
        String name = input.next();
 
        //Create a line space
        System.out.println();
 
        //Display list of products for customer
        System.out.println("GRAPEFRUIT PRODUCT" + '\n' +
                "1. gPod shuffle" + "   $" + GPOD_SHUFFLE + '\n' +
                "2. gPod Touch" + "     $" + GPOD_TOUCH + '\n' +
                "3. gPad Mini" + "      $" + GPAD_MINI + '\n' +
                "4. gPad 2" + "         $" + GPAD_2 + '\n' +
                "5. gPhone" + "         $" + GPHONE + '\n' +
                "6. gMac" + "           $" + GMAC + '\n' +
                "7. MacNovel Pro" + "   $" + MACNOVEL_PRO + '\n' +
                "8. MacNovel Air" + "   $" + MACNOVEL_AIR + '\n'+
                "9. MiniMac" + "        $" + MINIMAC + '\n' +
                "10. Complete my order");
 
 
 
 
    }//end main method
}//end class OnlineOrdering

I don't understand what type of loop I should be doing. If anyone can point me in the right direction, I'd be really grateful.

The customer can purchase as many items as they want. Each item corresponding to a number (1-9). The system will ask the user to enter another item until the user inputs 10. Then the total items ordered, price of items ordered, sales tax, and total amount due will be calculated.

I dont understand how the computer can total each individual item as 1. So if a customer picks items 1, 5, 2, 6, and 7, how does the computer read it as a total of 5 items and not the mathematical sum (21).

.

Ok update!
I redid my coding and was able to fix the problem.

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package orderfrommenu;
 
import java.util.Scanner;
 
/**
 *
 * @author jamesbottom
 */
public class OrderFromMenu {
 
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
 
        final int SENTINEL = 10;    //Number used to indicate loop termination
        int nCount = 0;		//Number of integers entered by user
        int nSum = 0;			//Sum of numbers entered by user
        int nNumber = 0;    //Number entered by user
        //Declare variables
        final int GPOD_SHUFFLE = 49;
        final int GPOD_TOUCH = 299;
        final int GPAD_MINI = 329;
        final int GPAD_2 = 399;
        final int GPHONE = 199;
        final int GMAC = 1299;
        final int MACNOVEL_PRO = 1199;
        final int MACNOVEL_AIR = 999;
        final int MINIMAC = 599;
        Scanner input = new Scanner(System.in);
 
 
        //Prompt user for name
        System.out.print("Please enter your name: ");
        String first = input.next();
        String last = input.next();
 
        //Create a space
        System.out.println();
 
 
        //Display list of products for customer
        System.out.println("GRAPEFRUIT PRODUCT" + '\n' +
                "1. gPod shuffle" + "   $" + GPOD_SHUFFLE + '\n' +
                "2. gPod Touch" + "     $" + GPOD_TOUCH + '\n' +
                "3. gPad Mini" + "      $" + GPAD_MINI + '\n' +
                "4. gPad 2" + "         $" + GPAD_2 + '\n' +
                "5. gPhone" + "         $" + GPHONE + '\n' +
                "6. gMac" + "           $" + GMAC + '\n' +
                "7. MacNovel Pro" + "   $" + MACNOVEL_PRO + '\n' +
                "8. MacNovel Air" + "   $" + MACNOVEL_AIR + '\n'+
                "9. MiniMac" + "        $" + MINIMAC + '\n' +
                "10. Complete my order");
 
        //Create a space
        System.out.println();
 
        //Prompt user to select an item from the menu
        System.out.print("Please select an item from the menu: ");
 
        //Read number from user
        nNumber = input.nextInt();
 
        //while user entered more integers, calculate the sum and count the numbers entered
        while (nNumber != SENTINEL) {
            System.out.print("Please select another item from the menu: ");
            nNumber = input.nextInt();
 
            //Accumulate sum
            nSum = nNumber + nSum;
 
            //Increment count
            nCount++;
        } //end while user did not enter 10
 
        //Create a space
        System.out.println();
 
        //Print Thank You message
        System.out.println("Thank you for ordering with Grapefruit Company, " + first + " "+ last);
        //Print count of numbers entered
        System.out.println("Total Items Ordered: " + nCount);

The only question I have now is, how would I calculate the price of the items selected.

}//end main method
}//end class OrderFromMenu

I don't know how to use arrays, or at the least, can't remember. Can you give an example?

B

Sorry if I wasn't clear, but our Teacher hasn't taught us about array's yet. Therefore we should be required to figure this out without them.
Thus, thats why I need to figure out the right combination of loops and if/elses.

H

@javaiscool. Thanks man, I think I'm on to something.

I imported the code:

if (nNumber == 1){
            nSum += GPOD_SHUFFLE;
        }
        else if (nNumber == 2){
            nSum += GPOD_TOUCH;
        }

When I ran the program, i put in a 1 and a 2 to test it. The problem is it gave me the price of only item 1, without item 2. Any clues?

In other words, if the user only wants item 1, the program will just give them the price of item 1. If they just want item 2, it will give them item 2. But I can't figure out how to give them the combination prices, i.e items 3,4,5,2,1,6 and not just one at a time.

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package orderfrommenu;
 
import java.util.Scanner;
 
/**
 *
 * @author jamesbottom
 */
public class OrderFromMenu {
 
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
 
        final int SENTINEL = 10;    //Number used to indicate loop termination
        int nCount = 0;		//Number of integers entered by user
        int nSum = 0;			//Sum of PRICES entered by user
        int nNumber = 0;    //Number entered by user
        //Declare variables
        final int GPOD_SHUFFLE = 49;
        final int GPOD_TOUCH = 299;
        final int GPAD_MINI = 329;
        final int GPAD_2 = 399;
        final int GPHONE = 199;
        final int GMAC = 1299;
        final int MACNOVEL_PRO = 1199;
        final int MACNOVEL_AIR = 999;
        final int MINIMAC = 599;
 
        Scanner input = new Scanner(System.in);
 
 
        //Prompt user for name
        System.out.print("Please enter your name: ");
        String first = input.next();
        String last = input.next();
 
        //Create a space
        System.out.println();
 
 
        //Display list of products for customer
        System.out.println("GRAPEFRUIT PRODUCT" + '\n' +
                "1. gPod shuffle" + "   $" + GPOD_SHUFFLE + '\n' +
                "2. gPod Touch" + "     $" + GPOD_TOUCH + '\n' +
                "3. gPad Mini" + "      $" + GPAD_MINI + '\n' +
                "4. gPad 2" + "         $" + GPAD_2 + '\n' +
                "5. gPhone" + "         $" + GPHONE + '\n' +
                "6. gMac" + "           $" + GMAC + '\n' +
                "7. MacNovel Pro" + "   $" + MACNOVEL_PRO + '\n' +
                "8. MacNovel Air" + "   $" + MACNOVEL_AIR + '\n'+
                "9. MiniMac" + "        $" + MINIMAC + '\n' +
                "10. Complete my order");
 
        //Create a space
        System.out.println();
 
        //Prompt user to select an item from the menu
        System.out.print("Please select an item from the menu: ");
 
        //Read number from user
        nNumber = input.nextInt();
 
        if (nNumber == 1){
            nSum += GPOD_SHUFFLE;
        }
        else if (nNumber == 2){
            nSum += GPOD_TOUCH;
        }
 
        //while user entered more integers, calculate the sum and count the numbers entered
        while (nNumber != SENTINEL) {
            System.out.print("Please select another item from the menu: ");
            nNumber = input.nextInt();           
 
 
            //Increment count
            nCount++;
 
        } //end while user did not enter 10
 
 
 
        //Create a space
        System.out.println();
 
        //Print Thank You message
        System.out.println("Thank you for ordering with Grapefruit Company, " + first + " "+ last);
        //Print count of numbers entered
        System.out.println("Total Items Ordered: " + nCount);
 
        //Print price
        System.out.println("Price of items ordered: " + nSum);
 
 
 
    }//end main method
}//end class OrderFromMenu

* I noticed it only works if I keep it in that area of the code. If I put it in the while loop, it does nothing. Also, I just put the 2 products as a test. I know I will eventually have to put all of them.

The while loop asks the user to enter a number for a product. Until they enter the integer 10 (the sentinel), it will keep asking them for a product number.

ex.
Please select an item from the menu: 5
Please select another item from the menu: 3
....
and so forth until they hit 10.

One of my teacher assistants just suggested I put the println for all the products into the while loop. I dont see how that makes sense because I don't want that list to be regenerated every time the user puts in an integer.

Sorry to sound like a pain but thats the problem I'm having. I honestly have no idea how to move on.

.