Using break and continue

1. Using break and continue Examples for using the break and continue keywords: • Example 3.5: TestBreak.java • Example 3.6: TestContinue.java

2. // TestBreak.java: Test the break keyword in the loop,15public class TestBreak { /** Main method */ public static void main(String[] args) { int sum = 0; int item = 0; while (item < 5) { item ++; sum += item; //if (sum >= 6) break; } System.out.println("The sum is " + sum); }}

3. // TestContinue.java: Test the continue keyword,13 • public class TestContinue { • /** Main method */ • public static void main(String[] args) { • int sum = 0; • int item = 0; • while (item < 5) { • item++; • if (item == 2) continue; • sum += item; • } • System.out.println("The sum is " + sum); • } • }

4. 3.7 Finding the Sales Amount You have just started a sales job in a department store. Your pay consists of a base salary and a commission. The base salary is $5,000. The scheme shown below is used to determine the commission rate. Sales Amount Commission Rate $0.01–$5,000 8 percent $5,000.01–$10,000 10 percent $10,000.01 and above 12 percent Your goal is to earn $30,000 in a year. Write a program that will find out the minimum amount of sales you have to generate in order to make $30,000.

5. // FindSalesAmount.java: Find the sales amount to get the • // desired commission.Base salary 5000,earn30000 a yr. • import javax.swing.JOptionPane; • public class FindSalesAmount { • /** Main method */ • public static void main(String[] args) { • // The commission sought • final double COMMISSION_SOUGHT = 25000; • final double INITIAL_SALES_AMOUNT = 0; • double commission = 0; • double salesAmount = INITIAL_SALES_AMOUNT; • do { • // Increase salesAmount by 1 cent • salesAmount += 0.01;

6. // Compute the commission from the current salesAmount; • if (salesAmount >= 10000.01) • commission = • 5000 * 0.08 + 5000 * 0.1 + (salesAmount - 10000) * 0.12; • else if (salesAmount >= 5000.01) • commission = 5000 * 0.08 + (salesAmount - 5000) * 0.10; • else • commission = salesAmount * 0.08; • } while (commission < COMMISSION_SOUGHT); • // Display the sales amount • String output = • "The sales amount $" + (int)(salesAmount * 100) / 100.0 + • "\nis needed to make a commission of $" + COMMISSION_SOUGHT; • JOptionPane.showMessageDialog(null, output, • "Example 3.7 Output", JOptionPane.INFORMATION_MESSAGE); • System.exit(0); • }

7. 3.8 Displaying a Pyramid of Numbers In this example, you will use nested loops to print the following output: 1 212 32123 4321234 543212345 Your program prints five lines. Each line consists of three parts. The first part comprises the spaces before the numbers; the second part, the leading numbers, such as 3 2 1 on line 3; and the last part, the ending numbers, such as 2 3 on line 3.

8. // PrintPyramid.java: Print a pyramid of numbers • public class PrintPyramid { • /** Main method */ • public static void main(String[] args) { • final int NUM_OF_LINES = 5; • for (int row = 1; row <= NUM_OF_LINES; row++) { • // Print leading spaces • for (int column = 1; column <= NUM_OF_LINES - row; column++) • System.out.print(" "); • // Print leading numbers • for (int num = row; num >= 1; num--) • System.out.print(num); • // Print ending numbers • for (int num = 2; num <= row; num++) • System.out.print(num); • // Start a new line • System.out.println(); • } • } • }

9. 3.9 Displaying Prime Numbers • This example displays the first 50 prime numbers in five lines, each of which contains 10 numbers. An integer greater than 1 is prime if its only positive divisor is 1 or itself. For example, 2, 3, 5, and 7 are prime numbers, but 4, 6, 8, and 9 are not. • The problem can be broken into the following tasks: • For number = 2, 3, 4, 5, 6, ..., test whether the number is prime. • Determine whether a given number is prime. • Count the prime numbers. • Print each prime number, and print 10 numbers per line.