311: Mainline

Now you can define the power_of_2 function using a for loop instead of a while loop. The initialization expression, counter = n, assigns the value of the parameter n to counter. Then, as long as the value of counter is not 0, the value of result, whose initial value is 1, is multiplied by 2 and the value of counter is decremented by 1.

int power_of_2 (int n) { 
  int counter, result = 1; 
  for (counter = n; counter; counter = counter - 1) 
    result = 2 * result; 
  return result; 
}