The difference is that the do while loop executes at least once because it checks for the loop condition while exiting. While is a entry controlled loop and do while is a exit control loop. Whereas in do while loop it will enter the loop and will then check for the condition.
while loop - used for looping until a condition is satisfied and when it is unsure how many times the code should be in loop
for loop - used for looping until a condition is satisfied but it is used when you know how many times the code needs to be in loop
do while loop - executes the content of the loop once before checking the condition of the while.
