Using a Boolean Sentinel to Control a While Loop

Suppose you work at a music store for minimum wage plus a 12.5% commission on sales. Write a program that allows you to enter your daily sales. The program should print the total and number of sales for the day plus your commission. You should be able to enter any number of sales for the day. When you are finished for the day, type in 0 (zero) to stop entering sales and print your commission report. Here is a sample run:

This program uses a Boolean variable to control the loop and shows you how to use counters and accumulators.

Heres some pseudocode to help you get started:

import a scanner

import a currency formatter

In the main method

Setup scanner and currency number formatter

Declare a constant for the commission percent

Declare variables for the current sale, the total sales (accumulator) and the number of sales (counter)

Declare a Boolean loop control variable done and initialize it to false

While (not done)

{

Prompt for current sale

If (current sale = 0)

{

done = true

}

Else

{

Accumulate total sales

Count sales

}

} // end of while loop

Print the total sales and number of sales

Print the commission

Youll find my solution on the next page. Yours may differ. Try to write the program first the review my solution.

package whileloopbooleansentinel;

import java.text.NumberFormat;

import java.util.Scanner;

/**

* @author Larry Waldrop

*/

public class WhileLoopBooleanSentinel

{

public static void main(String[] args)

{

// TODO code application logic here

Scanner input = new Scanner(System.in);

NumberFormat currency = NumberFormat.getCurrencyInstance();

final double COMMISSION_PERCENT = 0.125;

// be sure to initialize boolean variable

boolean done = false;

double currentSale, commission;

// initialize counters and accumulators

double totalSales = 0.0; // accumulator

int numSales = 0; // counter

while (!done) // while not done

{

System.out.print("Enter sales: ");

currentSale = input.nextDouble();

if (currentSale == 0.0)

{

done = true; // we are done

}

else // we are not done

{

// accumulate and count sales

totalSales = totalSales + currentSale;

numSales = numSales + 1;

}

}

// compute commission

commission = totalSales * COMMISSION_PERCENT;

// output results

System.out.println();

System.out.printf("Today you made %d sales totaling %s%n", numSales,

currency.format(totalSales));

System.out.printf("You commission on today's sales is %s%n",

currency.format(commission));

}

}

run: Enter sales: 212.45 Enter sales: 36.20 Enter sales: 9.73 Enter sales: 12.46 Enter sales: 38.20 Enter sales: 57.41 Enter sales: 125.86 Enter sales: 330. 67 Enter sales: 0 Today you made 8 sales totaling $822.98 You commission on today's sales is $102.87 BUILD SUCCESSFUL (total time: 42 seconds)