What are the three types of loops in Java?
In programming, many features make coding easy. One such feature is called loops. Loops is one of the most popular programming features, and it exists in almost all programming languages.
It provides an essential function of programming called iteration. Iteration in programming means repeating a set of instructions multiple times. Since Java is one of the most popular programming languages, let’s learn about what are loops in Java and their components, along with the types of loops in Java.
This guide will help you understand loops in Java if you are a newbie and have just started to learn Java language,
Let’s get started!
What are loops in Java, and how does it work?
In programming, if you want to repeat an action, you can write the set of instructions repeatedly, but instead, we use a loop in programming.
Using a loop, you can do the same thing as many times as you want without writing those statements that many times. It is a very important feature as sometimes some actions must be repeated not once or twice but hundreds of times.
A loop in Java works by writing a looping statement that keeps repeating until the boolean expression turns false. Here is a simple example of a loop in Java.
Input
Output
In the above example, there is a code that prints “Loop + i,” where i is equal to 1 when the code starts. The value of “i” increases by 1 until the value of “i” reaches 5 as there is a “smaller than or equal to” comparison operator used in the code.
The code has printed “Loop + i” every time with the updated value of “i” until it reached 5. But once the value of “i” exceeds 5, the code stops printing as the boolean expression becomes false.
What are the components of a loop in java?
Initialization expression
Before entering the loop, initialization expression is carried out once. Hence, you can either choose to initialize a variable you will use in the loop or declare and initialize a control variable. Also, you can initialize multiple variables as well.
Test expression
The test expression is the expression that is used for the termination of the loop. It is always a boolean expression which, if found false, terminates the loop.
Body of the loop
The loop’s body contains the code, which has to be executed iteratively. It will get continuously executed until the boolean expression turns false.
Update expression
The update expression is the line of code that contains the loop variable. It increases or decreases the value of the loop variable after every iteration.
What are the types of loops in Java?
Now that you know what loops are in Java, let’s discuss the types of loops in Java. There are three loops in Java: for loop, while loop, and do while. So, let’s discuss these types of loops in detail.
For Loop
For loop is the most used loop of Java. It is the most straightforward loop in java. In “for loop,” you just have to put the instructions that have to be done in the loop. Now, by defining the number of iterations, you can start a for loop in java.
Input
Output
In the above example of for-loop execution, you can see that the number of iterations is less than or equal to 5. So, the execution will stop once the statement becomes false.
While Loop
‘While` loop in Java is used in cases where the number of iterations is unknown. It continues executing as long as the specified condition becomes true. Moreover, it is necessary to include the code that changes the condition in a while loop. It ensures the loop will eventually terminate.
Input
Output
Here in the while loop example, the loop will continue to execute the program until the condition of “count<= 5” remains true. Instead of defining the number of iterations, we have specified the number of loops we want by putting the count value.
Do-While Loop
The third and last loop in Java is the `do-while.` It is similar to the `while` loop but guarantees that the loop body is executed at least once before checking the condition. It is because the condition is evaluated after the loop body.
Input
Output
Here, in the do-while loop example, we have again mentioned the number of times we need the loop instead of the number of iterations.
So, it is similar to the while loop till here. However, the catch is that it prints the body at least once, even if the condition does not meet from the first iteration.
As you can see in the above code, the count should be smaller than or equal to 0. But the very the first iteration is 1, which is greater than 0. Still, the outcome is “Loop 1”.
How to learn the Java language?
Java is among the most popular programming languages. It is widely used everywhere, from software to devices, so it is essential for a programmer to learn Java language. Another reason to learn Java language is that many other languages are based on Java’s syntax.
However, learning Java can be a bit challenging. So, you should start to learn the Java language from its basics. You should keep yourself patient throughout the learning period as you may continuously encounter hard-to-solve problems.
To learn Java, the best resource can be coding tutorial videos and books related to Java language. Also, if you are starting to learn Java language in your school or college, which is when most people do, then try to learn Java in groups to better understand its concepts.
Final Words
The loop is an essential feature in Java and other programming languages as it facilitates repetitive tasks, which is very important in programming.
You should learn the implementation of all three types of loops in Java. Moreover, since you know what loops are in Java and how to use them, start practicing them as much as possible.
