Lesson Overview

Welcome to the thrilling realm of iterations and loops. In this lesson, let's dive into Dart's while and do while loops! While loops play a vital role in programming due to their ability to execute code blocks repeatedly until a specific condition becomes false. They operate similarly to performing an action until a condition changes — such as washing a car until it's completely clean. A while loop operates until the condition becomes false. Conversely, a do while loop will execute the code block at least once, regardless of the condition.

The Syntax of While Loops

A while loop in Dart consists of a condition and a code block. The code block is executed if the given condition is true.

What are While Loops?

while loops in Dart are control flow statements that enable a specific code block to execute repeatedly while a certain condition holds true. For example, imagine a scenario where you continue reading a book while the light is on. Here's what a while loop in Dart might look like:

Introducing Do While Loops

The do while loop in Dart is similar to the while loop, but with one crucial difference: the code block within the do while loop will execute at least once, even if the condition is not met. Here's the general syntax for a do while loop in Dart:

And here's a simple practical example:

In this example, despite the counter being initialized at 5 which does not satisfy the condition counter < 5, the code block is still executed once. Hence, 5 is printed out.

Practical Examples with While Loops

Suppose you need to execute a countdown from the number 5 to 0. You can quickly achieve this using a while loop as follows:

Compound Conditions with While Loops

while loops in Dart can use compound conditions with && (and) or || (or). For instance, imagine a situation where you're saving up for a new device and aim to stop saving once you reach your target, or when the sales season ends — whichever occurs first:

Common Pitfalls in Using While Loops

Be careful to avoid creating an endless loop in Dart, where the condition always remains true, leading to an infinite loop. This situation can occur when the increment step is missing, as shown in the example below:

Lesson Summary and Practice

Congratulations! You've mastered the use of while loops, grasped their syntax, and implemented them in real-world scenarios. Now it's time to delve deeper with some practical exercises to strengthen these skills. Enjoy your journey into the Dart world, and prepare for exciting adventures ahead!

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