Learn to Program with Small Basic

15
25
Average = 17.5
The program prompts the user to enter four numbers and press enter
after each number. It reads these numbers, one by one, and saves them in
four variables: n1, n2, n3, and n4 (lines 4–7). It then computes the average of
these numbers, saves the average in the variable avg (line 8), and displays
the result (line 9).
Listing 6-6 shows a different way to write this program. Enter this program,
and then run it. This time you’ll use just one variable named sum.
1 ' Avg2.sb
2 TextWindow.Write("Enter 4 numbers. ")
3 TextWindow.WriteLine("Press after each one:")
4 sum = TextWindow.ReadNumber()
5 sum = sum + TextWindow.ReadNumber()
6 sum = sum + TextWindow.ReadNumber()
7 sum = sum + TextWindow.ReadNumber()
8 TextWindow.WriteLine("Average = " + (sum / 4))
Listing 6-6: Finding the average of four numbers using an accumulator
To understand how the program works, let’s say the user entered the
numbers 10, 20, 15, and 25 in response to the prompt. So, in line 4, sum
becomes 10. In line 5, the second number (20) is added to the first number
(10) and saved to the sum variable (totaling 30). In lines 6–7, the third
number (15) and fourth number (25) are added and saved to sum (totaling
70). The program then displays the average, which is sum / 4, to the user
(line 8).
Because of how the sum variable keeps adding input to itself (or accumulating),
it’s known as an accumulator (also known as a running sum). (This
might be similar to how you accumulate hairbands or Pokémon cards, but
these numbers only take up computer memory and don’t clutter your room.)
Reading Text
Next, let’s write a simple program that makes silly sentences using the
words in Shakespeare’s famous quote: “To be or not to be: that is the question.”
You’ll ask the user to enter two verbs and a noun, and then you’ll use
these entries to replace the words be, be, and question in Shakespeare’s quote.
Listing 6-7 shows the complete program.
1 ' Silly.sb
2 TextWindow.Write("Please enter a verb: ")
3 verb1 = TextWindow.Read()
4
5 TextWindow.Write("Please enter another verb: ")
6 verb2 = TextWindow.Read()
7
8 TextWindow.Write("Now, please enter a noun: ")
Getting User Input 79