Summary  
This chapter introduces the while loop, a control structure that repeatedly executes a block of code as long as a Boolean condition remains true, and highlights the importance of updating loop variables to ensure the condition eventually becomes false to avoid infinite loops.

General domain of usage  
Iterative data processing

## while Loop

The `while` loop is the simplest example of a loop in action. This loop will repeatedly execute a code block as long as the condition inside the `condition` block evaluates to `true`. Once the condition returns `false`, the loop execution will stop.

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The `while` loop works as follows:

- The condition is checked before each iteration; if true, the loop runs, if false, it ends;
- The loop can contain one or more statements, executed repeatedly while the condition is true;
- Ensure the condition eventually becomes false to avoid an infinite loop.


Here's an example to demonstrate the ``while`` loop:



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In our loop, we set a condition that reads as follows: as long as the value of variable `a` is not equal to the value of variable `b`, we increment variable `a` and decrement variable `b`. When their values are equal, we terminate the `while` loop.


package com.example;

import org.junit.jupiter.api.DynamicTest;
import org.junit.jupiter.api.TestFactory;

import java.util.Map;
import java.util.stream.Stream;

import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.DynamicTest.dynamicTest;

public class MainTest {

    @TestFactory
    Stream<DynamicTest> testSumFrom1ToN() {
        Map<Integer, Integer> inputToExpected = Map.of(
                1, 1,
                2, 3,
                3, 6,
                4, 10,
                5, 15,
                10, 55,
                0, 0,
                -5, 0
        );

        return inputToExpected.entrySet().stream().map(entry -> {
            int input = entry.getKey();
            int expected = entry.getValue();
            int actual = Main.sumFrom1ToN(input);

            boolean passed = actual == expected;
            String testName = passed
                    ? "sumFrom1ToN(" + input + ") returned " + actual + " as expected."
                    : "sumFrom1ToN(" + input + ") returned " + actual + ", but expected " + expected + ".";

            return dynamicTest(testName, () -> {
                assertEquals(expected, actual);
            });
        });
    }
}

MainTest.java

Learn the fundamentals of Java and its key features in this course. By the end, you'll be able to solve simple algorithmic tasks and gain a clear understanding of how basic console Java applications operate.

Discover the unique features of Java and understand why it's a recommended programming language to learn. Write your first Java code and explore how to print text to the console.

Learn the basics of programming, dive into primitive data types, and explore operations with them. Write code that performs mathematical tasks and evaluates conditions for seamless execution.

Explore various loops such as for, while, and do-while, which are essential in any programming language. Loops enable efficient iteration over large datasets, saving significant time. Apply them extensively in tasks like sorting, working with arrays, collections, and more.

Learn how to effectively use arrays in Java programming by discovering how to group data into arrays and exploring common methods and properties for working with them. Techniques for manipulating and optimizing arrays in real-world applications will also be examined.

Learn about String, a crucial data type in Java, and discover its many built-in methods and operations. Explore String and StringBuilder, understanding their basic methods and how to use strings effectively in Java.

While-Loop

while Loop

Solution