Page 217 - Learn To Program With Scratch

The script selects a word randomly from a list and saves that word
in inWord u. It then sets strIn equal to inWord v and calls Randomize to
shuffle the characters of strIn w. After that, the script starts a loop to get
the player’s answer x. Inside the loop, the script asks the player to enter the
unscrambled word y and uses an if/else block to check that answer z. This
part is identical to what we did in the Fix My Spelling game in the previous
section.
The previous examples were just a small set of the different operations
you can do on strings. Try using the same techniques to change strings in
your own projects!
In the rest of this chapter, we’ll explore some programs that use strings
to solve interesting problems.

Scratch Projects

The procedures you just saw demonstrated the basics of processing strings.
In this section, we’ll apply what we’ve learned to write several practical appli-
cations. Along the way, you’ll learn some new programming tricks that you
can use in your own creations.

Shoot

Shoot .sb2 This game is intended to teach the concept of relative motion in a fun and
engaging way. The object of the game is to estimate the turn angle and
moving distance between two objects on the Stage. The user interface for
the game is illustrated in Figure 8-14.

In this example, the
player needs to turn
about 50°, and then Target sprite
move about 220 steps
to hit the target.

Player sprite

Helper sprite
(invisible)

Figure 8-14: The user interface of the Shoot game

When the game starts, it positions the Player and the Target sprites at
random locations on the Stage. Next it prompts the player to estimate the
turn angle and the distance the Player sprite would need to move to hit the
Target. The Player sprite is then moved according to the numbers entered by
the player. If the sprite stops within a certain radius of the Target, the player

String Processing 195

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