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.
A while
loop in Dart consists of a condition and a code block. The code block is executed if the given condition is true.
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:
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.
Suppose you need to execute a countdown from the number 5 to 0. You can quickly achieve this using a while
loop as follows:
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:
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:
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!
