Important: The break and continue keywords provide additional loop control mechanisms. These keywords can simplify programming in some cases, but excessive or improper use can make programs harder to read and debug.

public class TestBreak {
  public static void main(String[] args) {
    int sum, number;

    sum = 0;
    number = 0;
    while (number < 20) {
      number++;
      sum += number;
      if (sum >= 100) 
        break;
    }
    System.out.println("The number is " + number);
    System.out.println("The sum is " + sum);
  }
}

public class TestContinue {
  public static void main(String[] args) {
    int sum, number;
    
    sum = 0;
    number = 0;
    while (number < 20) {
      number++;
      if (number == 10 || number == 11) 
        continue;
      sum += number;
    }
    System.out.println("The sum is " + sum);
  }
}

Important: The continue statement is always inside a loop body. In while and do-while loops, the loop repetition condition is evaluated immediately after the continue statement. In a for loop, the loop control variable is updated first, then, immediately after continue, the loop repetition condition is evaluated.

int factor = 2;
while (factor <= n) {
  if (n % factor == 0)
    break;
  factor++;
}
System.out.println("The smallest divisor other than 1 for "
  + n + " is " + factor);

boolean found = false;
int factor = 2;
while (factor <= n && !found) {
  if (n % factor == 0)
    found = true;
  else
    factor++;
}
System.out.println("The smallest divisor other than 1 for "
  + n + " is " + factor);

Lab 1: Break and Continue

Objective: Write a program that analyzes a sequence of numbers entered by the user and performs two actions:

1. Terminates input when a negative number is entered (break).
2. Skips even numbers when outputting (continue).

Expected Output:

Enter numbers (negative number ends input):
Number 1: 5
Odd number: 5
Number 2: 8
8 — even, skipping.
Number 3: 3
Odd number: 3
Number 4: -1
Negative number entered. Ending input.
Total numbers processed: 3

File Name: L9Lab1.java
Class Name: L9Lab1

Algorithm:

1. Step 1. Environment Preparation and Class Import
   • Create a new Java file named L9Lab1.java.
   • Import the Scanner class for input.
   import java.util.Scanner; public class L9Lab1 { public static void main(String[] args) { Scanner scanner = new Scanner(System.in);
2. Step 2. Variable Declaration
   • Create variables for the current input number (number) and a counter for processed numbers (count).
   int number; int count = 0;
3. Step 3. Organizing an Infinite Loop with while
   • Use while (true) to continue the loop until explicitly terminated with break.
   System.out.println("Enter numbers (negative number ends input):"); while (true) { System.out.print("Number " + (count + 1) + ": "); number = scanner.nextInt();
4. Step 4. Checking for Negative Number (break)
   • If a negative number is entered, display a message and break the loop.
   if (number < 0) { System.out.println("Negative number entered. Ending input."); break; }
5. Step 5. Increment Counter and Check for Even Numbers (continue)
   • Increment the counter. If the number is even, skip further processing using continue.
   count++; if (number % 2 == 0) { System.out.println(number + " — even, skipping."); continue; }
6. Step 6. Output Odd Numbers
   • If the number is odd (and not negative), output it.
   System.out.println("Odd number: " + number); }
7. Step 7. Final Output After Loop Completion
   • Show how many numbers were processed before termination.
   System.out.println("Total numbers processed: " + count); scanner.close(); } }
8. Run the program (e.g., press F5 in your IDE).
9. Test with different values to see the output.
10. Upload the file to the learning management system.

Task 1: Break - Stop at 7

To do: Output numbers from 1 to 10, but break the loop as soon as the number 7 is encountered.

Expected Output:

File Name: L9Task1.java

Task 2: Continue - Skip Multiples of 3

To do: Output all numbers from 1 to 15, except numbers divisible by 3 (use continue).

Expected Output:

File Name: L9Task2.java

Task 3: Break and Continue - Complex Conditions

To do: Output numbers from 1 to 20, but skip numbers ending in 5, and break the loop at number 17.

Expected Output:

File Name: L9Task3.java

Task 4: Break and Continue with Strings

To do: Traverse a string character by character. Output only letters (skip digits and special characters). If the character '!' is encountered, break the loop.

Expected Output:

File Name: L9Task4.java

Task 5: Rewrite TestBreak and TestContinue

To do: Rewrite the TestBreak and TestContinue programs without using break and continue.

TestBreak: The TestBreak program calculates the sum of integers from 1 to 20 until the sum is greater than or equal to 100.

TestContinue: The program sums integers from 1 to 20, excluding 10 and 11.

File Name: L9Task5.java