3.1 Lesson Outcomes
After completing this lesson, learners will be able to:
- Use for loops in Java.
- Apply while loops.
- Use do-while loops.
- Apply nested loops.
- Use break and continue statements.
3.2 Overview
Loops allow Java programs to repeat instructions multiple times. Java provides several looping structures used for iteration and repetitive execution.
The main loop structures are:
- for loop,
- while loop,
- do-while loop,
- and enhanced for loop.
Loops are important in:
- data processing,
- arrays,
- collections,
- calculations,
- and automation.
Understanding loops is important because repetition is a major part of software development.
PA1501 — Use for Loops
The for loop repeats instructions for a specified number of times.
Java Example:
for (int i = 1; i <= 5; i++) {
System.out.println(i);
}
Practical Activity
Learners must:
- create for loops,
- control iteration,
- and display repeated output.
PA1502 — Use while Loops
The while loop executes while a condition remains true.
Java Example:
int i = 1;
while (i <= 5) {
System.out.println(i);
i++;
}
Practical Activity
Learners must:
- create while loops,
- control conditions,
- and display results.
PA1503 — Use do-while Loops
The do-while loop executes at least once before checking conditions.
Java Example:
int i = 1;
do {
System.out.println(i);
i++;
} while (i <= 5);
Practical Activity
Learners must:
- create do-while loops,
- test conditions,
- and display repeated output.
PA1504 — Use Enhanced for Loops
Enhanced for loops simplify iteration through arrays and collections.
Java Example:
int[] numbers = {1, 2, 3, 4, 5};
for (int num : numbers) {
System.out.println(num);
}
Practical Activity
Learners must:
- create enhanced for loops,
- iterate arrays,
- and display values.
PA1505 — Use Nested Loops
Loops can exist inside other loops.
Java Example:
for (int i = 1; i <= 3; i++) {
for (int j = 1; j <= 2; j++) {
System.out.println(i + “ “ + j);
}
}
Practical Activity
Learners must:
- create nested loops,
- apply multiple iterations,
- and display output.
PA1506 — Use break Statement
The break statement terminates loop execution.
Java Example:
for (int i = 1; i <= 10; i++) {
if (i == 5) {
break;
}
System.out.println(i);
}
Practical Activity
Learners must:
- apply break statements,
- terminate loops,
- and test results.
PA1507 — Use continue Statement
The continue statement skips the current iteration.
Java Example:
for (int i = 1; i <= 5; i++) {
if (i == 3) {
continue;
}
System.out.println(i);
}
Practical Activity
Learners must:
- apply continue statements,
- skip iterations,
- and display outputs.
PA1508 — Create Complete Loop Program
Loops are used in complete Java applications.
Java Example:
public class LoopExample {
public static void main(String[] args) {
for (int i = 1; i <= 5; i++) {
System.out.println(“Java Loop “ + i);
}
}
}
Importance of Loops
Loops support:
- repetition,
- automation,
- iteration,
- and efficient software development.
3.5 Key Notes / Summary
- for loops repeat instructions a fixed number of times.
- while loops execute while conditions remain true.
- do-while loops execute at least once.
- Enhanced for loops simplify iteration.
- Nested loops support multiple repetitions.
- break terminates loops.
- continue skips iterations.