Learn to Program with Small Basic

9 pos = Math.GetRandomNumber(len) ' Picks where to place the letter
10 If (char[pos] "") Then
11 strout = strout + char[pos] ' Adds in the extra letter
12 char[pos] = "" ' Empties the element
13 EndIf
14 EndWhile
15 EndSub
Listing 18-10: Word-scrambling subroutine
The subroutine saves the length of the input string into len (line 2).
It then uses a For loop to save the individual letters of strIn into an array
named char (lines 3–5). It empties the output string, strOut, and starts a
While loop to assemble strOut letter by letter (lines 7–14). The While loop
runs until strOut has the same length as strIn (which means that we’ve
added all the letters of strIn). Each iteration of the loop picks a random
element from the char array (line 9). If that element is empty, we loop again
to pick another one. Otherwise, we append the selected letter to strOut
(line 11) and empty that element to indicate that we’ve used it (to prevent
using it again) in line 12. Ouy fishendi eth egma!
Here’s a sample run of this program:
Unscramble [lalvey]: lovely
No. It is valley.
TRY IT OUT 18-9
Try to update the word-scrambling game using the skills you learned in previous
chapters. Make the game last 10 rounds and then display the user’s score: how
many words were unscrambled correctly out of the 10? Next, add 28 more words
to unscramble so you have a total of 50. Then show the game to your friends and
see who can get the best score!
Rhyme Time: The House That Jack Built
Let’s finish this chapter with a program that displays a popular British
nursery rhyme and cumulative tale. In a cumulative tale, an action repeats
and builds up as the tale progresses. Figure 18-7 shows this program
in progress; more rhyme lines appear each time a user clicks the Next
button.
280 Chapter 18