Learn to Program with Small Basic

Going Interactive
Let’s explore how to get the students’ scores from the user rather than
hardcoding them within the program like we did in Listing 17-3. We’ll use
two loops to iterate over the students’ names and subjects, as shown in the
following pseudocode (you’ll learn how to translate this pseudocode into
real code in a moment):
For each student in the array: [Scott, Jean, Logan]
For each subject in the array: [Math, Science, Combat]
score[student][subject] = read score from user
EndFor
EndFor
You can save the names of the students in a one-dimensional array,
save the names of the subjects in another one-dimensional array, and then
use nested For loops with integer indices to access the individual elements
of these two arrays. Then you can use the strings (student name and subject)
as indices for a score matrix. Check out Listing 17-4 to see the code in
action.
1 ' StudentAvg2.sb
2 nameList = "1=Scott;2=Jean;3=Logan;"
3 subjList = "1=Math;2=Science;3=Combat;"
4
5 For I = 1 To 3 ' Three students
6 name = nameList[I] ' Name of the Ith student
7 For J = 1 To 3 ' Three subjects
8 subj = subjList[J] ' Name of Jth subject
9 TextWindow.Write(name + "'s " + subj + " score: ")
10 score[name][subj] = TextWindow.ReadNumber()
11 EndFor
12 EndFor
13 TextWindow.Write("Enter student name: ")
14 name = TextWindow.Read()
15 sum = score[name]["Math"]
16 sum = sum + score[name]["Science"]
17 sum = sum + score[name]["Combat"]
18 avg = Math.Round(sum / 3)
19 TextWindow.WriteLine(name + " average score = " + avg)
Listing 17-4: Reading scores from the user
The program starts by creating the name and subject arrays (lines 2–3).
Then a nested loop starts to fill the score matrix. The outer loop iterates
over the students, and the inner loop iterates over the subjects.
The outer loop starts with I = 1. Here name gets assigned to nameList[1],
which is "Scott" (line 6). Then the inner loop runs three times, the first
time with J = 1, and subject gets assigned to subjList[1], which is "Math"
248 Chapter 17