Rotating a String solution (idea)

There's a simpler, more intuitive solution, which also more efficient. The trick is :

• Take the first letter.
• Compute where it should go after the rotate (addition with a modulo)
• Save the target letter in a temp variable X
• Replace the target letter by the first letter
• Compute where should X go after the rotate
• etc... n times, n being the length of the string.

Here a python snippet (sorry about the closing brackets, i don't know how to escape them):

def rotate_string(string, d):
     old_char = string[0)
     current_index = 0
     for i in range(len(string)):
          target_index = (current_index + d) % len(string)
          temp_char = string [ target_index )
          string [ target_index ) = old_char
          current_index = target_index
          old_char = temp_char
    return string