Proj. # 13 - Introduction to BASIC :

The following simple programs illustrate QBASIC syntax for simple processes. Using QBASIC enter and run each of the following programs. Try to determine how the output was produced from the program commands.

Procedure

• First run the QBASIC integrated programming environment.
  
• Enter and run each of the programs below.
  
• To print out a program click on File followed by Print. Then < > Current Module, then <OK>
  
• To print out the output of the RUN press <Print Screen> or if in Windows <Shift><Print Screen>
  
• To print out a graphics screen, it is best not to be in Windows, go to your Disk A: or B: and type Graphics, then run QBASIC and your program.

Prog 1: Type in the following program

1. Run it 3 times using different values for the radius.

   SCREEN 9
   INPUT "Radius"; radius CIRCLE (200, 200), radius, 2 ' 2 is color green
   LINE (100, 100)-(100 + radius, 100 + radius), 3, B ' 3 is blue

2. Describe what happens and why?

3. Print out program and RUNs.

Prog 2 : Finding Prime Numbers

1. Enter the following Program

   CLS
   INPUT "Type in an integer number greater than 2 ", N
   LPRINT "Your number is "; N A$ = "YES"
   FOR Test = 2 TO SQR(N)
   IF INT(N / Test) = N / Test THEN A$ = "NO": PRINT "Divisor:"; Test
   NEXT Test
   PRINT "This is a PRIME number?.. "; A$ _

2. Run the program for a few sample numbers.

3. Are the following number are PRIME: 1101, 1001, 1111, 123, 321,123 001.

4. Find three new PRIME numbers greater than 100 000.

   _______________ ___________________ ______________

5. Print a listing of the program and the run for the following numbers

   2000 and 3001.

Prog 3 : Simulation of Coin Flips

1. Type in the program

   RANDOMIZE TIMER
   INPUT "How many flips"; Num
   PRINT "Number of flips "; Num
   Heads = 0
   FOR Flip = 1 TO Num
   IF RND > .5 THEN Heads = Heads + 1
   NEXT Flip
   PRINT "Percent of Heads = "; Heads / Num * 100; "%"

2. Run the program and print out each run for 10, 100, 1000, 10 000 flips..

3. What do you notice about the percentage of Heads?

4. What is the theoretical % of Heads?  Write out answer on the printouts!!

5. Change PRINT statement to LPRINT in each line of the program

6. Analysis of Cion Flipping :

   1. Run the program for 10 000 flips.

   2. Then run the program again for as many HEADS as your last run.

   3. Repeat this process until there are 59 or less HEAD's

7. A Sample of the runs are given below:

   How many flips? 10 000
   # of Heads = 5060

   How many flips? 5060
   # of Heads = 2549

   How many flips? 2549
   # of Heads = 1257

   How many flips? 1257
   # of Heads = 629

   How many flips? 629
   # of Heads = 298

   How many flips? 298
   # of Heads = 143

8. After you have run the program, put the data in table form. Illustrated below :

   Trial #	Num Heads
   1	10000
   2	5060
   3	2549
   4	1257
   5	629
   6	298
   7	143

9. Use the CORCO program with this data to determine which mathematical function could generate this data.

10. You are THE DETECTIVE use CORCO to determine what type of mathematical function best fits the data.    Is it a Straight Line, Exponential, or Power?  

11. Here is a sample of what your graph in CORCO would look like.

    

12. For the best curve fit choose the function with the value of R closest to 1.  Type _________

13. Print out a graph of the best Corco fit.

14. Write out the best fit function on the printout and comment on the correlation coefficient!

Prog 4 : Grpahics

1. Enter the following program

   RANDOMIZE TIMER
   SCREEN 12
   FOR Picture = 1 TO 50
   X = 30 + RND * 550
   Y = 30 + RND * 300
   Radius = RND * 50
   Color1 = RND * 12
   Color2 = RND * 12
   CIRCLE (X, Y), Radius, Color1
   CIRCLE (X, Y), Radius + 1, Color1
   PAINT (X, Y), Color2, Color1
   NEXT Picture

2. Describe what you see when you run the program 3 different times.

3. Print out a listing of the program and one of the graphics.

4. Make the following changes and run the modified program:

   RANDOMIZE TIMER
   SCREEN
   FOR Pic = 1 TO 500
   X = 30 + RND * 550
   Y = 30 + RND * 300
   Radius = RND * 100
   COLOR1 = RND * 12
   COLOR2 = RND * 12
   LINE (X, Y)-(X + Radius, Y + Radius), COLOR1, B
   LINE (X, Y)-(X + Radius + 1, Y + Radius + 1), COLOR1, B
   PAINT (X + 2, Y + 2), COLOR2, COLOR1
   NEXT Pic

5. Describe what you see when you run the program 3 times.

6. Print out a listing of the program and one of the graphics.

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