Karel J Robot - Chapter 5 Programs: Repeating Instructions BACK TO KAREL MAIN
Instructions that Repeat
We will now learn how to make Karel perform repetitive tasks. In other words, we will learn how to make a command that can cause Karel to perform an action over and over. You will see that this saves many lines of code. In computer science, the act of repeating a block of code is called a loop. There are two types loops we will use: the for loop and the while loop. See the examples below. |
The FOR loop – a loop used when you want a robot to perform the same task a specific number of times. Example 1: a for loop used to make exactly 5 moves: public void move() Example 2: a for loop used to make n moves: public void move(int n) |
The WHILE loop – a loop used when you want a robot to perform a task repeatedly until a condition becomes false (an unknown number of times). Example 1: a while loop used to make a robot move to a wall an unknown distance away: public void moveToWall() Example 2: a while loop used to pick up an unknown number of beepers at its current location: public void pickAllBeepers() |