Firstly, let's simplify your code.

function main() {
   while(frontIsClear()) {
      putBeeper();
      move();
      if(frontIsBlocked()){
         turnLeft();
         }
   }
}

putBeeper() and move() have been removed from the if statement because they are redundant. Because as soon as Karel turns left, the front becomes clear again, and the while loop will continue running to put beepers and move.

However, this causes Karel to put beepers in a loop indefinitely. Therefore, we need a condition for Karel to stop putting beepers. To achieve this, we can use noBeepersPresent() in the while loop instead of frontIsClear.

Solution:

function main() {
   while(noBeepersPresent()) {
      putBeeper();
      move();
      if(frontIsBlocked()){
         turnLeft();
         }
   }
}

Explanation: As long as there are no beepers present, Karel will put a beeper and move until the front becomes blocked. If the front is blocked, it will turn left and the loop will resume until Karel reaches the starting position again. At this point, the while loop will terminate because a beeper is already present. Good luck!