Is while (true) with break bad programming practice?

Question

I often use this code pattern:

while(true) {

    //do something

    if() {
        break;
    }

}   

Another progr

Answer 1

The problem is that not every algorithm sticks to the "while(cond){action}" model.

The general loop model is like this :

loop_prepare
 loop:
  action_A
  if(cond) exit_loop
  action_B
  goto loop
after_loop_code

When there is no action_A you can replace it by :

loop_prepare
  while(cond)
  action_B
after_loop_code

When there is no action_B you can replace it by :

loop_prepare
  do action_A
  while(cond)
after_loop_code

In the general case, action_A will be executed n times and action_B will be executed (n-1) times.

A real life example is : print all the elements of a table separated by commas. We want all the n elements with (n-1) commas.

You always can do some tricks to stick to the while-loop model, but this will always repeat code or check twice the same condition (for every loops) or add a new variable. So you will always be less efficient and less readable than the while-true-break loop model.

Example of (bad) "trick" : add variable and condition

loop_prepare
b=true // one more local variable : more complex code
 while(b): // one more condition on every loop : less efficient
  action_A
  if(cond) b=false // the real condition is here
  else action_B
after_loop_code

Example of (bad) "trick" : repeat the code. The repeated code must not be forgotten while modifying one of the two sections.

loop_prepare
action_A
 while(cond):
  action_B
  action_A
after_loop_code

Note : in the last example, the programmer can obfuscate (willingly or not) the code by mixing the "loop_prepare" with the first "action_A", and action_B with the second action_A. So he can have the feeling he is not doing this.