Java Control Structures

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When venturing into the world of Java programming, it's essential to understand how control structures work. They contribute to the flow of your code and determine how it behaves under different conditions. In this article, we'll explore conditional statements, such as if-else, as well as loops, including for, while, and do-while, in Java.

Conditional Statements

Conditional statements enable your code to make decisions based on specific conditions. The most common conditional statement in Java is the if-else statement.

If-Else Statements

The if-else statement evaluates a condition and executes a block of code if the condition is true. Optionally, an else block can be added to execute when the condition is false. Let's look at an example:

int age = 18; if (age >= 18) { System.out.println("You are an adult."); } else { System.out.println("You are not an adult."); }

In this example, we check if the age variable is greater than or equal to 18. If it is, we print "You are an adult"; otherwise, we print "You are not an adult."


Loops are a fundamental part of programming, allowing you to repeat a block of code multiple times. Java offers three primary loop structures: for, while, and do-while loops.

For Loops

For loops are perfect for iterating through a known number of elements, such as arrays or lists. Here's a basic example:

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

This loop iterates five times, printing "Iteration" followed by the current value of i. The loop starts with i equal to 0 and increments it by 1 (i++) on each iteration until i is no longer less than 5.

While Loops

While loops continue iterating as long as a specified condition is true. Let's look at an example:

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

In this example, the loop will execute as long as the counter variable is less than 5. It prints "Counter" followed by the current value of counter and then increments counter by 1 on each iteration.

Do-While Loops

A do-while loop is similar to a while loop, but it guarantees that the loop will execute at least once, even if the condition is false from the start. Here's an example:

int number = 10; do { System.out.println("Number: " + number); number++; } while (number < 5);

In this case, the loop will execute once, printing "Number: 10", even though number is not less than 5. After the first iteration, the condition is checked, and the loop exits because the condition is false.

With a solid understanding of Java's control structures, you'll be better equipped to write efficient and effective code. Remember to use the appropriate loop or conditional statement based on your specific requirements, and your Java programs will be in tip-top shape!

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