Learn to Program with Small Basic

Condition 1
True
Statement set 1
If (condition 1) Then
Statement set 1
False
Condition 2
True
Statement set 2
ElseIf (condition 2) Then
Statement set 2
False
Condition x
True
Statement set x
--snip--
ElseIf (condition x) Then
Statement set x
False
Default statements
Else
Default statements
EndIf
Figure 9-1: The structure of the If/ElseIf ladder
Let’s look at another way to use the If/ElseIf ladder.
Letter Grades
In this example, you’ll create a program that reads a test score between 0
and 100, and displays a letter grade from Table 9-1.
Table 9-1: Letter-Grade Scores
Score
score ≥ 90
A
80 ≤ score < 90 B
70 ≤ score < 80 C
60 ≤ score < 70 D
score < 60
F
Letter grade
The complete program is shown in Listing 9-2.
1 ' GradeLetter.sb
2 TextWindow.Write("Enter the score: ")
3 score = TextWindow.ReadNumber()
4 If (score >= 90) Then
5 grade = "A"
6 ElseIf (score >= 80) Then
7 grade = "B"
8 ElseIf (score >= 70) Then
9 grade = "C"
10 ElseIf (score >= 60) Then
11 grade = "D"
Using Decisions to Make Games 113