Starter Look at the hand-out. Could you program the robot to light all the squares up? What instructions would you give it?

Python - Iteration Iteration Iteration is a posh way of saying “loop” (iteration literally means to do something again). Loops are absolutely vital in programming in order to avoid having to write sequences of code out again and again. And they come in several forms:

Python - Iteration While Loops A WHILE loop is a way of repeating a section of code. It is easy to understand because it uses something that looks a lot like an IF statement at the top.

Python - Iteration How many times do you think this loop will repeat? Try it and find out: number = 1 while number < 10: print(“This is turn ”,number) number = number + 1 print(“The loop is now finished”) Make sure you understand why the last line only prints out once, at the end of the loop.

Python - Iteration A WHILE loop is ideal if you don’t know exactly how many times you will need to repeat the code.

Python - Iteration targetNumber = 7 # ask for a guess # this is the correct number targetNumber = 7 # ask for a guess guess = int(input(“Guess a number between 1 and 10”)) # repeat if the answer is wrong while guess != targetNumber: print(“Wrong, try again”) guess = int(input(“Guess a number between 1 and 10”)) # do this after the loop print(“Congratulations - that’s right!”)

Python - Iteration Tasks Create a program that gets two players to enter in their names and then you choose a Gamenumber between 10 and 50. Each player takes it in turns to choose either 1,2 or 3. This number is then deducted from the Gamenumber. The last person to deduct a number from the Gamenumber before it reaches 0 loses.

Python - Iteration Solution – Pseudo Code Playing = 1 GameNumber = INPUT Valid = false While GameNumber > 0 While Valid = false Get number from user if number 1,2 or 3 and Gamenumber – number >= 0 Valid = true GameNumber – number Show GameNumber if GameNumber > 0 if Playing = 1 Playing = 2 else IF playing = 1 THEN OUTPUT “Player 2 loses” ELSE OUTPUT “Player 1 loses” END IF