Learn to Program with Small Basic

This piece of code simply says, “As long as ans is not equal to num, run
the statement(s) between the While and the EndWhile keywords.”
First, the test condition (ans num) is evaluated. If it’s true, the program
runs the statements in the loop’s body and keeps repeating until the
condition becomes false. When the test condition becomes false, the loop
ends, and the program moves to the next statement after the EndWhile keyword.
The flowchart in Figure 14-1 illustrates how the While loop works.
Condition?
False
True
Execute statements in
the body of the
While loop.
Move to the statement after
the EndWhile keyword.
Figure 14-1: Flowchart of the While loop
In the number-guessing game, when the program runs line 4 for
the first time, the condition (ans num) is true (because we know that
num can’t be 0), and the loop runs the statements in its body (lines 5–13).
During each iteration of the loop, the player is prompted to enter a guess
(line 5), which is saved into the variable ans (line 6). The code then compares
the player’s guess with the secret number. If the player guessed correctly
(line 7), the code displays Good Job! You get sprinkles! and moves to
the statement after EndIf. In this example, it finds EndWhile, which takes your
program back to check the condition of the While loop. Because ans is now
equal to num, the test condition is false and the While loop terminates, ending
the program (because there are no statements after EndWhile).
If the player’s guess was incorrect, the code checks whether the guess
was higher than the secret number (line 9). If it’s higher, the program displays
Too High. Lower your standards. Then the loop goes for another round.
If the player’s guess is lower than the secret number (the Else statement
on line 11), the program displays Too Low. Aim for the stars! (line 12) and
starts another round.
Here is an example of a rather lucky user playing the game:
Enter your guess [1-100]: 50
Too High. Lower your standards.
Enter your guess [1-100]: 25
Too Low. Aim for the stars!
Enter your guess [1-100]: 37
Good Job! You get sprinkles!
Play this game several times to see how it works!
Creating Conditional While Loops 197