Why while(true) is bad practice? [closed]

Question

I use while true loop in many projects. It serves me well and it's not over-complicated. So, why it is a bad idea to use while true loop infinitely running background processes. Thanks for your answers.

Answer 1

My project leader doesn't allow this kind of loop in my code, he's arguing that it has to be replaced by while(!exit_flag)

That's very debatable. while (!exit_flag) suggests that the loop has a natural exit condition which it will reach at some specific point by itself, e.g. something counting from 0 to 100 and then leaving the loop. However, if you are writing this loop to create a permanent daemon or event loop, then the point of this loop is to keep the program running indefinitely. Nothing says indefinitely better than while (true).

There's no real technical difference between both; it's just a matter of readability and expression of intent. Of course, you'll have to square this with the people who will read that code in the end. If their policy is while (!exit_flag), so be it.

Answer 2

It is not a bad practice, it just means that you did not think your code through.

The condition is required to tell the loop when to finish looping. If you have a terminating point, then why not put it as a condition?

var i = 0;
while(true){
   i++;
   if(i == 100)
      break;
}

This is fine code. But so is this:

var i = 0;
while(i != 100){
   i++;
}

Both methods are correct, but if someone else is reading your code, it is much easier to see when the loop will stop iterating if it is right there in the condition.