Answer 1

Let the compiler do its job and optimize your loops, just use the type that makes your code easiest to understand.

Answer 2

All loops are roughly equivlent performance wise. The type you choose is really up to you and the task you are trying to achieve.

Answer 3

If you really want to look at the most optimal looping, you will have to consider hand optimizing by unrolling the operations

Answer 4

use while loop when you dont know how many times the loop will occur.. use for loops when u know the amount of times the loop will occur.

Answer 5

Use for loop because it reduces lines of code