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Loops in Java

Introduction​

Loops in Java are used to execute a block of code repeatedly until a specified condition is met. They are essential for tasks that require repetition, such as iterating over arrays or performing a series of calculations.

Types of Loops​

For Loop​

The for loop is used when you know in advance how many times you want to execute a statement or a block of statements.

Syntax:

for (initialization; condition; update) {
    // code to be executed
}

Example:

for (int i = 0; i < 5; i++) {
    System.out.println("Iteration: " + i);
}

Enhanced For Loop (For-Each Loop)​

The enhanced for loop, also known as the for-each loop, is used to iterate over elements in arrays or collections.

Syntax:

for (type element : array) {
    // code to be executed
}

Example:

int[] numbers = {1, 2, 3, 4, 5};
for (int number : numbers) {
    System.out.println("Number: " + number);
}

While Loop​

The while loop is used when you do not know in advance how many times you need to execute a block of code. It repeats the block as long as the specified condition is true.

Syntax:

while (condition) {
    // code to be executed
}

Example:

int i = 0;
while (i < 5) {
    System.out.println("Iteration: " + i);
    i++;
}

Do-While Loop​

The do-while loop is similar to the while loop, but it ensures that the code block is executed at least once before checking the condition.

Syntax:

do {
    // code to be executed
} while (condition);

Example:

int i = 0;
do {
    System.out.println("Iteration: " + i);
    i++;
} while (i < 5);

Control Statements​

Break Statement​

The break statement is used to exit a loop prematurely when a certain condition is met.

Example:

for (int i = 0; i < 10; i++) {
    if (i == 5) {
        break;
    }
    System.out.println("Iteration: " + i);
}

Continue Statement​

The continue statement is used to skip the current iteration of the loop and proceed to the next iteration.

Example:

for (int i = 0; i < 10; i++) {
    if (i == 5) {
        continue;
    }
    System.out.println("Iteration: " + i);
}

Nested Loops​

You can nest loops within each other to handle more complex situations.

Example:

for (int i = 0; i < 3; i++) {
    for (int j = 0; j < 3; j++) {
        System.out.println("i: " + i + ", j: " + j);
    }
}

Conclusion​

Loops are fundamental constructs in Java that help execute code repeatedly based on specified conditions. Understanding how to use for, while, and do-while loops, along with control statements like break and continue, is essential for efficient programming.