What are the differences between do while and while loops in PHP, and when should each be used?

The main difference between a do while loop and a while loop in PHP is that a do while loop will always execute the code block at least once before checking the condition, while a while loop will only execute the code block if the condition is true. A do while loop should be used when you want to guarantee that the code block is executed at least once, regardless of the condition. On the other hand, a while loop should be used when you want to execute the code block only if the condition is true. Example: ``` // Using a do while loop $counter = 0; do { echo "The counter is: $counter <br>"; $counter++; } while ($counter < 5); // Using a while loop $counter = 0; while ($counter < 5) { echo "The counter is: $counter <br>"; $counter++; } ```