Course Content

Java Basics

1. Getting Started

Backend Development Role of Java in the Backend Java Advantages Memory Types In Java Java's Syntax Your First Program Comments

2. Basic Types and Operations

Primitive Data Types Challenge: Primitive Types Mathematical Operations on char Mathematical Operations in Java If-Else Statement Switch-Case Statement New Task Structure Challenge: Weekday Switch

3. Loops

Introduction to Loops While-Loop Do-While Loop Challenge: Building a Server Retry Mechanism For-Loop Increment and Decrement Infinite Loop Challenge: Filtering Numbers in a Loop

4. Arrays

What is Array?Using Loops with Arrays Index Out Of Bounds Two-Dimentional Array Iteration In Two-Dimensional Array For-Each Loop

5. String

What Is String? Basic Methods In String Practical Applications of String Methods Challenge: Filter Failure Messages NullPointerException StringBuilder String Pool, Method Equals() Summary

Introduction to Loops

What if we need to repeat a code fragment many times? For example, our boss assigned us an incredible task: displaying the same message on the screen 1,000 times. Can you imagine how you would spend the whole day typing System.out.println(); over and over again?

But here, loops come to the rescue!

In Java, there are several types of loops, each better suited for specific tasks. Throughout the next section, you will explore each of them and understand where and when it is best to use them.

Let's scale down the task a bit and say that we need to display the same message 5 times. We'll use the copy-paste method:

Main


              1234567891011
            
package com.example;

public class Main {
    public static void main(String[] args) {
        System.out.println("Hey, I will appear here 5 times");
        System.out.println("Hey, I will appear here 5 times");
        System.out.println("Hey, I will appear here 5 times");
        System.out.println("Hey, I will appear here 5 times");
        System.out.println("Hey, I will appear here 5 times");
    }
}

As we can see, we have completed the task and displayed the text on the screen five times.

Now, all we have to do is display this text on the screen only 995 more times, and the task will be complete.

So, let's use a loop that will perform a specific operation until the loop's execution condition becomes false:

Main


              1234567891011
            
package com.example;

public class Main {
    public static void main(String[] args) {
        int number_of_operations = 0;
        while (number_of_operations < 10) {
            System.out.println("Hey, I will appear here 10 times");
            number_of_operations = number_of_operations + 1;
        }
    }
}

In the code above, we used a loop. However, it's worth noting that initially, we declared the variable number_of_operations to count how many times we performed the operation. Then we set a condition that this variable should have a value less than 10, which means the loop will execute until the variable's value reaches 10. We will explore the operation of specific loop examples in more detail in the following chapters.

1. What is a loop?

2. What is the purpose of loops?

Everything was clear?

Thanks for your feedback!

Section 3. Chapter 1

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Course Content

Java Basics

1. Getting Started

Backend Development Role of Java in the Backend Java Advantages Memory Types In Java Java's Syntax Your First Program Comments

2. Basic Types and Operations

Primitive Data Types Challenge: Primitive Types Mathematical Operations on char Mathematical Operations in Java If-Else Statement Switch-Case Statement New Task Structure Challenge: Weekday Switch

3. Loops

Introduction to Loops While-Loop Do-While Loop Challenge: Building a Server Retry Mechanism For-Loop Increment and Decrement Infinite Loop Challenge: Filtering Numbers in a Loop

4. Arrays

What is Array?Using Loops with Arrays Index Out Of Bounds Two-Dimentional Array Iteration In Two-Dimensional Array For-Each Loop

5. String

What Is String? Basic Methods In String Practical Applications of String Methods Challenge: Filter Failure Messages NullPointerException StringBuilder String Pool, Method Equals() Summary

Introduction to Loops

But here, loops come to the rescue!

In Java, there are several types of loops, each better suited for specific tasks. Throughout the next section, you will explore each of them and understand where and when it is best to use them.

Let's scale down the task a bit and say that we need to display the same message 5 times. We'll use the copy-paste method:

Main


              1234567891011
            
package com.example;

public class Main {
    public static void main(String[] args) {
        System.out.println("Hey, I will appear here 5 times");
        System.out.println("Hey, I will appear here 5 times");
        System.out.println("Hey, I will appear here 5 times");
        System.out.println("Hey, I will appear here 5 times");
        System.out.println("Hey, I will appear here 5 times");
    }
}

As we can see, we have completed the task and displayed the text on the screen five times.

Now, all we have to do is display this text on the screen only 995 more times, and the task will be complete.

So, let's use a loop that will perform a specific operation until the loop's execution condition becomes false:

Main


              1234567891011
            
package com.example;

public class Main {
    public static void main(String[] args) {
        int number_of_operations = 0;
        while (number_of_operations < 10) {
            System.out.println("Hey, I will appear here 10 times");
            number_of_operations = number_of_operations + 1;
        }
    }
}

1. What is a loop?

2. What is the purpose of loops?

Everything was clear?

Thanks for your feedback!

Section 3. Chapter 1