Just use whichever loop seems more appropriate to the task at hand. In general, you should use a for loop when you know how many times the loop should run. If you want the loop to break based on a condition other than the number of times it runs, you should use a while loop.

When to use do-while instead of while?

Do-while loops can be useful when you know you want the code to run at least once (a while loop will not run at all if the condition it checks for is false beforehand, but a do-while loop will run once before it checks).

Why do we use while loops?

A "While" Loop is used to repeat a specific block of code an unknown number of times, until a condition is met. For example, if we want to ask a user for a number between 1 and 10, we don't know how many times the user may enter a larger number, so we keep asking "while the number is not between 1 and 10".