This lab is a kind of crash course in basic programming techniques that are common to all programming languages. You might find it moves a little too quickly for you (it usually takes 3-4 weeks to cover this in a regular programming class), and you are highly encouraged to read (and reread) the text if you have any additional questions. Working with variables, loops and conditionals is something you will probably pick up over time as you develop your own video games, so it's not critically important if you're still mystified at the end of this lab. My goal is to give you the basic tools in this class that can let you explore independently after the class is over.
Read Chapter 2 and Chapter 3 through the top of p52
Variables
Types
Input
Conditionals if, switch
Relational and logical operators
Loops while, goto, repeat
Write your answers after completing the lab. TURN IN : the last program printout you worked on + your answer to these 4 questions next week.
1) Determine the output of: 2) Determine the output of: x = 31 y = 13 x=31 y=13 z = x - y
Print "x – y =" + z
If x >= y Then
Print x + "is bigger"
Else Print y + "is bigger"
EndIf
3) Determine the output of:
For counter = 5 To 50 Step 20
Print counter
Next
4) Determine the output of:
For counter = 5 To 50 Step 20
If counter > 35
Print counter
EndIf
Next
1

Part 1.
Using print to display text
;demo02-01.bb - Displays text "Hello World"
Print "Hello, World!"
;Wait for the user to press a key
WaitKey
Notes print is a function
The general syntax of Print Print [string$]
Try
Print two lines of text
Use Print with no argument
Change Print to Write and see what happens
Part 2.
Variables
Three kinds of variables
Declaring variables
Using variables
;demo02-02.bb - Adds too cool numbers
;VARIABLES favnum = 314 coolnum = 13
;Print the two variables
Print "I like " + favnum + " And I like " + coolnum ; A
;Print the variables added together)
Print "These numbers added together are " + (favnum + coolnum) ;B
WaitKey
Notes
A) you can make a string with numbers inside it using +
B) If you want to force arithmetic put parentheses around the variables that you're adding
C) store a 10 into coolnum Then display what's inside coolnum with a descriptive message ( should say coolnum=10)
D) store the product of coolnum and favnum into coolnum, then display what's inside coolnum with a descriptive message ( should say coolnum=3140)
E) add a third variable to the program called temp, then see if you can exchange the values stored in favnum and coolnum using temp for temporary storage
2

;demo02-03.bb - adds strings together string1$ = "I " string2$ = "like " string3$ = "programming!"
;concatenate the strings completestring$ = string1$ + string2$ + string3$ ; A
;print 'em out
Print completestring$
WaitKey
Notes
A) change the order of the string variables around in line ;A and see what happens
;demo02-04.bb asks user's name and shows it
;get the user's name name$ = Input$("Hi! May I know your name please? ")
Print "Hi " + name$ + "."
WaitKey
Notes
A) Input is a new function to get data from the user and store in a variable (in this case, name$)
B) input returns a string, but if you store the results in an integer variable you can use it to return integers as well
C) Declare another variable for age and read in the person's age
D) Declare another variable for year. Calculate the year the person was born using
2005-age and store the result inside the variable year, then display the year the person was born.
Part 3.
Using different branching techniques (relational and logical expressions, if, if-else)
;demo02-05.bb - Tests if you are old enough to vote
;Find out how old the user is age = Input$("How old are you? ")
;if older or equal to 18, print out confirmation that user is allowed to vote.
If age >= 18 Then
EndIf
Print "You are legally allowed to vote!"
WaitKey
;demo02-06.bb - Tests if you are old enough to vote age = Input$("How old are you? ") ;how old is user
If age >= 18 Then
Print "You are legally allowed to vote!" ;if older or equal to 18
Else Print "Sorry, you need To be a few years older." ;if younger than 18
EndIf
WaitKey
3

;demo02-07.bb - Tests if you are old enough to vote
;find out how old the user is age = Input$("How old are you? ")
;if exactly 18, write that voting is legal
If age = 18 Then
Print "You can now vote."
;if older tha 18, write out that voting has been legal for a while
Else If age > 18
Print "You've been able to vote for a while."
;if younger than 18, write out that voting is illegal.
Else If age < 18
EndIf
Print "Sorry, you will have to wait a few years to vote."
WaitKey
Notes
A) Notice the different forms, draw flowcharts in the margin indicating the way they work
B) Modify demo 2_7 to classify a person based on their age. It should identify whether they are senior citizens, adults, teenagers, children, or infants
;demo02-08.bb - tests the keys pressed x = Input$("Enter 1 to say hi, or 0 to quit. ")
Select x
Case 1
Print "Hi!"
Case 0
End
Default
Print "Huh?"
End Select
WaitKey
Notes
A) modify the previous example to display one of five mystery messages depending on what number the person types
;demo02-09.bb - Shows use of the And operator
;find out how old the user is age = Input$("How old are you? ")
;find out if the user lives in america location = Input$("Do you live in America? (1 For yes, 2 For no) ")
;Write out the proper string depending on the user's age and locations
4

If age >= 18 And location = 1 Then
Print "Congrats, you are eligible to vote!"
Else
EndIf
Print "Sorry, you can't vote."
WaitKey
Notes
A) modify the previous example to determine if a person is an adult using an and to chain two age range tests together.
B) modify the previous example to determine if a person is not an adult using an or to chain two age range tests together.
Part 4.
Using different looping techniques (goto, while, repeat)
;demo02-10.bb - Demonstrates the use of Goto
;Place a label
.label
Print "Hello"
;Does user want to repeat? selection = Input("Enter 1 if you want me to repeat 'Hello' ==> ")
If (selection = 1)
;Go to the top and print hello again
Goto label
EndIf
End
Notes
A) Draw a flowchart of the above code in the margin
B) Add a second label after hello called .label2 and Print "there" after it. Add a second condition (selection 2) that sends the program back to label2
C) Draw a flowchart of your modification in the margin
;demo03-01.bb - counts from 1 to 10
;start counter at one and loop till 10
For counter = 1 To 10
;Print whatever counter is equal to
Next
Print counter
WaitKey
Notes
A) Draw a flowchart of the above code in the margin
B) Change the loop so it counts from 15 to 25
C) Change Print to Write – What happens?
5

;demo03-02.bb - Counts backwards using step amounts
;start counter at 5 and loop till 0 by -1.2
For counter# = 5.0 To 0.0 Step -1.2
;Print value of counter
Print counter
Next
WaitKey
Notes
A) Modify above to count down from 25 in steps of 5, stopping at 0
;demo03-03.bb.bb - Counts using step amounts
;loop backwards, from 5.0 to 0.0 by -1.2
For counter# = 5.0 To 0.0 Step -1.2
;print out 3 digits of counter, so 5.000000 becomes 5.0
Print Left$( Str counter, 3)
Next
WaitKey
Notes
A) Modify above to step up from 1 to 2 in steps of 0.1234. and modify to display 6 digits of counter
;demo03-04.bb - Waits for a key and then exits
Print "This program is worthless."
Print "Press escape to exit."
;Wait until user presses 1 to Escape
While Not KeyDown(1)
Wend
End
;demo03-05.bb - Closes program after player presses ESC.
Print "Why did you open this progam?"
Repeat
Print "Press Esc to exit."
;wait a sec
Delay 1000
;repeat until user hits esc
Until KeyHit(1)
Print "Program is ending."
Notes
A) Copy the for loop from Demo3_3 into the code above after Repeat.
6

Part 5.
Application: Drawing Pictures with Nested Loops
;box drawing prog
For y = 1 To 7
For x=1 To 4
Write "*"
Next
Print
Next
WaitKey
Notes
A) draw the flowchart & show what shape the above program produces .
B) modify it to produce a box with 9 rows and 12 columns.
;empty box drawing prog
; draw the first line
Write "*"
For x=1 To 10
Write "*"
Next
Print "*"
; Draw the middle section
For y = 1 To 4
Write "*"
For x=1 To 10
Next
Write " "
Print "*"
Next
; Draw the last line
Write "*"
For x=1 To 10
Write "*"
Next
Print "*"
WaitKey
Notes
A) draw the flowchart & show what shape the above program produces .
B) modify it to produce a box with 9 rows and 12 columns.
7

For Fun!
Try drawing (using only Write and Print, using only one '*' or ' ' at a time, and using loops as shown above:
A) 2 boxes side by side separated by 8 spaces
***** *****
***** *****
***** *****
B) Basic checkerboard
*********
*********
*********
*********
*********
*********
*********
*********
*********
*********
C)
A right triangle (Hint: use for y = 1 to 7 then for x=1 to y …etc.)
*
**
***
****
*****
******
*******
D) A left triangle (this is even harder!)
*
**
***
****
*****
******
*******
8

Part 6.
Guessing Game
1) Play the guessing game demo2_11
2) Try the optimal strategy for guessing: the binary search algorithm. Always guess the midpoint between the range of possible values.
3) Mods to Guessing Game a.
redo the game without using goto: i.
remove the line label ii.
at the beginning, set guess to 0 iii.
then use a while loop like while guess <> numbertoguess to repeat the main game loop section b.
then put a for loop around the while loop to play 5 sessions of the game, make sure you reset the guess to 0 (and other init tasks) before each game. c.
Try to award points in such a way that a quicker guess gives a higher score: this could be a math formula for example
1 guess 10 points
5 guesses 2 points
10 guesses 1 points (can you figure out the formula)
9