Do you know the difference between do-while and while loops? If you’re a beginning programmer, you might not. Luckily, it’s pretty easy to explain.
Do-while and while loops have many similarities, but they are used in different situations. In this post, we will go over the differences between the two looping structures and when you would use one versus the other.
It can be tricky to understand all of these concepts at first, so try reading this article more than once if necessary.
After reading through it once or twice, though, you should be able to tell your friends about why you would use a do-while loop instead of a while loop in certain situations. Let’s get started!
What is a While Loop?
A while loop is a programming structure that allows you to execute code as long as a certain condition holds true.
In other words, a while loop will execute code again and again until that code does not meet certain requirements anymore.
If a while loop is not preceded by a condition, it will execute code indefinitely, which can cause problems in your program. This is called an infinite loop.
A while loop is often used in conjunction with a boolean condition, or an if/then statement.
For example, you might have a while loop that looks something like this: while the number of customers in line is greater than zero, keep selling items until the line is gone. This while loop will continue to run until the number of customers in line is equal to zero.
What is a Do-While Loop?
A do-while loop is similar to a while loop: it runs code over and over until a certain condition is met.
The only real difference between the two is that do-while loops always run at least once, whereas while loops may not run at all if the condition is not met.
This means that you can use a do-while loop for conditions that must always be met: for example, as long as there are customers in line, keep selling items. Although a while loop could also be used, it may not run at all in this scenario.
A do-while loop is often used when you must be certain that a certain piece of code runs at least once. This can be useful in many different situations, such as when you want to make sure that data is written to a file.
When to use a While Loop
A while loop is often used in programming to iterate through a list of items or to wait for a certain condition to be met.
If a while loop is used to iterate through a list, you will often use a boolean condition to specify when to stop looping.
For example, if you’re iterating through a list of numbers, you may want to loop until you get to a certain number such as the square root of the total number of numbers in the list. If a while loop is used to wait for a condition to be met, you may specify what condition the loop will stop on in the beginning of the loop. For example, a loop that waits for a web page to load might look something like this: while the web page does not load, keep trying to load it.
When to use a Do-While Loop
A do-while loop is usually used when you want to make sure that a certain piece of code runs at least once.
This is especially useful when you want to be sure that data that should be saved to a file or database is written correctly. For example, if you’re writing data to a file and you want to make sure that the file is saved even if an error occurs, you can implement a do-while loop. A do-while loop can also be used when you want to make sure that data is written in a specific order.
Summary
A while loop is often used in programming to iterate through a list of items or to wait for a certain condition to be met. A do-while loop is usually used when you want to make sure that a certain piece of code runs at least once. It is important to understand the difference between while and do while loops in order to create clean and effective code.
