Learn to Program with Small Basic

The program uses a variable named sum to hold the running total
(this variable is usually called an accumulator). The program starts by initializing
sum to 0 (line 2). Then a For loop with a loop counter named N runs
from 1 to 10 (line 3). During each iteration, the program adds the value
of N to the accumulator by using the statement at line 4. This statement
adds the current value of N to the current value of sum and stores the result
back into sum. After the first iteration, sum is 1 (0 + 1); after the second iteration,
sum is 3 (1 + 2); after the third iteration, sum is 6 (3 + 3); and so on.
When the loop ends, the program displays the value of the sum variable on
line 6: sum = 55.
TRY IT OUT 13-3
When the great mathematician Carl Gauss first went to school, his teacher asked
the class to find the sum of all the numbers between 1 and 100, that is, 1 + 2 +
3 + 4 + . . . + 100. Gauss took one look at the problem and immediately put his
answer on the teacher’s desk. The teacher was amazed—Gauss was right! Write
a program to find the answer that Gauss worked out in his head. Of course, Gauss
didn’t use Small Basic, but he did find a shortcut. Can you figure out his secret
method?
Formatting Your Output
The way you display the output of a
program is often just as important as
the information you display. If the output
is difficult to read, people won’t be
able to understand what the information
means. A well-laid-out display is an
essential part of your program design,
but getting the formatting right can be Figure 13-3: The output of
tedious. To make it easier, you can use SquareTable.sb
For loops. For example, let’s use a For
loop to write a program that outputs the
squares of 1 to 5 in a table format (see
Figure 13-3).
Enter and run the program in Listing 13-3.
1 ' SquareTable.sb
2 TextWindow.Title = "Table of Squares"
3 TextWindow.WriteLine(" Number Square")
4 TextWindow.WriteLine("======== =========")
5
6 For N = 1 To 5
7 TextWindow.CursorLeft = 3 ' Moves to middle of col 1
8 TextWindow.Write(N) ' Writes the number
Repeating For Loops 185