The_Official_Raspberry_Pi_-_Beginner’s_Book_Vol1,_2018 (1)

Chapter 4 Programming with Scratch^65

THE OFFICIAL RASPBERRY PI BEGINNER’S GUIDE

when clicked

set loops to^0

repeat^10

say loops for^2 secs

change loops by^1

Click the green flag again. This time, you’ll see the cat count upwards from 0 to 9. This
works because your program is now changing, or modifying, the variable itself: every time the
loop runs, the program adds one to the value in the ‘loops’ variable (Figure 4-7).

5 Figure 4-7: Thanks to the loop, the cat now counts upwards

COUNTING FROM ZERO

Although the loop you’ve created runs ten times, the cat

sprite only counts up to nine. This is because we’re starting

with a value of zero for our variable. Including zero and

nine, there are ten numbers between zero and nine – so the

program stops before the cat ever says ‘10’. To change this

you could set the variable’s initial value to 1 instead of 0.