Course Content
Introduction to PHP
Introduction to PHP
Do-While
The do-while
and while
loops are two types of loops in PHP used to repeat a block of code. However, there is a crucial difference between them:
The while
loop checks the condition before executing the code block, while the do-while
loop checks the condition after completing the code block.
It means that the while
loop may not execute at all if the condition does not evaluate to true
on the first check. On the other hand, the do-while
loop will consistently execute at least once, even if the condition does not evaluate to true
on the first check.
Syntax
We write commands that should work in a loop in the do
block of code. This is the condition that determines whether to continue iterating the loop.
Let's create a loop with a condition that will never be true
:
main
<?php $counter = 5; // Declare and initialize the variable do { echo 'Do-while loop'; $counter = $counter + 1; } while ($counter == 5); // Change the condition to 5 ?>
As you can see, the do-while
loop executed the code block at least once, even if the condition counter != 0 was not evaluated to true on the first check.
Here is another way to understand the difference between the do-while
and while
loops:
- The
while
loop is like checking before eating. You can only eat once you check if you are hungry; - The
do-while
loop is like eating before checking. You can eat, even if you are not hungry, and then check if you are still hungry.
Which type of loop to choose depends on your specific needs. Use a do-while
loop if you want the code block to execute at least once. If you do not wish for the code block to run if the condition does not evaluate to true
on the first check, use a while
loop.
Task
Fill in the blanks in the code to create a do-while
loop that prints even numbers from 2 to 10.
Thanks for your feedback!
Do-While
The do-while
and while
loops are two types of loops in PHP used to repeat a block of code. However, there is a crucial difference between them:
The while
loop checks the condition before executing the code block, while the do-while
loop checks the condition after completing the code block.
It means that the while
loop may not execute at all if the condition does not evaluate to true
on the first check. On the other hand, the do-while
loop will consistently execute at least once, even if the condition does not evaluate to true
on the first check.
Syntax
We write commands that should work in a loop in the do
block of code. This is the condition that determines whether to continue iterating the loop.
Let's create a loop with a condition that will never be true
:
main
<?php $counter = 5; // Declare and initialize the variable do { echo 'Do-while loop'; $counter = $counter + 1; } while ($counter == 5); // Change the condition to 5 ?>
As you can see, the do-while
loop executed the code block at least once, even if the condition counter != 0 was not evaluated to true on the first check.
Here is another way to understand the difference between the do-while
and while
loops:
- The
while
loop is like checking before eating. You can only eat once you check if you are hungry; - The
do-while
loop is like eating before checking. You can eat, even if you are not hungry, and then check if you are still hungry.
Which type of loop to choose depends on your specific needs. Use a do-while
loop if you want the code block to execute at least once. If you do not wish for the code block to run if the condition does not evaluate to true
on the first check, use a while
loop.
Task
Fill in the blanks in the code to create a do-while
loop that prints even numbers from 2 to 10.
Thanks for your feedback!
Do-While
The do-while
and while
loops are two types of loops in PHP used to repeat a block of code. However, there is a crucial difference between them:
The while
loop checks the condition before executing the code block, while the do-while
loop checks the condition after completing the code block.
It means that the while
loop may not execute at all if the condition does not evaluate to true
on the first check. On the other hand, the do-while
loop will consistently execute at least once, even if the condition does not evaluate to true
on the first check.
Syntax
We write commands that should work in a loop in the do
block of code. This is the condition that determines whether to continue iterating the loop.
Let's create a loop with a condition that will never be true
:
main
<?php $counter = 5; // Declare and initialize the variable do { echo 'Do-while loop'; $counter = $counter + 1; } while ($counter == 5); // Change the condition to 5 ?>
As you can see, the do-while
loop executed the code block at least once, even if the condition counter != 0 was not evaluated to true on the first check.
Here is another way to understand the difference between the do-while
and while
loops:
- The
while
loop is like checking before eating. You can only eat once you check if you are hungry; - The
do-while
loop is like eating before checking. You can eat, even if you are not hungry, and then check if you are still hungry.
Which type of loop to choose depends on your specific needs. Use a do-while
loop if you want the code block to execute at least once. If you do not wish for the code block to run if the condition does not evaluate to true
on the first check, use a while
loop.
Task
Fill in the blanks in the code to create a do-while
loop that prints even numbers from 2 to 10.
Thanks for your feedback!
The do-while
and while
loops are two types of loops in PHP used to repeat a block of code. However, there is a crucial difference between them:
The while
loop checks the condition before executing the code block, while the do-while
loop checks the condition after completing the code block.
It means that the while
loop may not execute at all if the condition does not evaluate to true
on the first check. On the other hand, the do-while
loop will consistently execute at least once, even if the condition does not evaluate to true
on the first check.
Syntax
We write commands that should work in a loop in the do
block of code. This is the condition that determines whether to continue iterating the loop.
Let's create a loop with a condition that will never be true
:
main
<?php $counter = 5; // Declare and initialize the variable do { echo 'Do-while loop'; $counter = $counter + 1; } while ($counter == 5); // Change the condition to 5 ?>
As you can see, the do-while
loop executed the code block at least once, even if the condition counter != 0 was not evaluated to true on the first check.
Here is another way to understand the difference between the do-while
and while
loops:
- The
while
loop is like checking before eating. You can only eat once you check if you are hungry; - The
do-while
loop is like eating before checking. You can eat, even if you are not hungry, and then check if you are still hungry.
Which type of loop to choose depends on your specific needs. Use a do-while
loop if you want the code block to execute at least once. If you do not wish for the code block to run if the condition does not evaluate to true
on the first check, use a while
loop.
Task
Fill in the blanks in the code to create a do-while
loop that prints even numbers from 2 to 10.