Simple java question: how do I convert this do-while loop to a while loop?

Question

Here is my do while loop for a program I'm writing for an assignment (I already declared radius as an int, and a Scanner named 'input' was already set up):

do {

System.out.print("Enter the radius (use a number " +

"between 10 and 250): ");

radius = input.nextInt();

if (radius < 10 || radius > 250)

System.out.println("Not following directions.");

} while (radius < 10 || radius > 250);

What it is supposed to do is print out "Enter the radius (use a number between 10 and 250): "

and the user will input a number. If they put in an appropriate number, the progrm moves onto another do-while statement asking for more input. If they put in a number not between 10 and 250, it's supposed to spit out "Not following directions." and then restarts the beginning instructions until the user puts in an appropriate number.

I can't seem to translate this into a while loop properly. I make it infinite, and I see my error, I just can't figure out how to remedy it. I'm obviously a beginner, so an example would be very useful.

Andrew S · Accepted Answer

while() and do...while() loops have different semantics, which is why both a provided. You always want to do this at least once (to get the value first time) so do...while() is the natural style. You have to slightly obfuscate your code with a deliberately invalid initialization to convert to a straight while() loop:

radius = 0;

while (radius < 10 || radius > 250) {