QBasic/Full Book View
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               Contents  [hide] 
      1 Text Output
        1.1 Print
        1.2 1HELLO.BAS
        1.3 Understanding 1HELLO.BAS
        1.4 2HELLO.BAS
        1.5 Commas and Semicolons in PRINT and CLS
        1.6 3HELLO.BAS
        1.7 Variables
        1.8 4FACE.BAS
        1.9 Locate statement
        1.10 5FACE.BAS
        1.11 Colors
        1.12 Color by Number
        1.13 Summary
      2 Basic Input
        2.1 6INPUT.BAS
      3 Basic Math
        3.1 Equation Setup
        3.2 7MATH.BAS
        3.3 Understanding 7MATH.BAS
        3.4 8MATH.BAS
        3.5 Understanding 8MATH.BAS
        3.6 9TIP.BAS
        3.7 Tip Calculator
        3.8 10OROP.BAS
        3.9 Parentheses and Order of Operations
        3.10 Random Numbers
        3.11 11RND.BAS
        3.12 More on RND
      4 Flow Control
        4.1 Conditional execution
        4.2 True or False
        4.3 IF
        4.4 IF...THEN...ELSE
        4.5 13 ELSEIF
        4.6 FOR...NEXT
        4.7 14FOR.BAS
        4.8 WHILE...WEND
        4.9 15WHILE.BAS
        4.10 DO...LOOP
        4.11 12IF.BAS
        4.12 SELECT CASE
      5 Advanced Input
        5.1 INKEY$
        5.2 The keyboard buffer
        5.3 Scancodes
      6 Subroutines and Functions
        6.1 Purpose
        6.2 Procedure vs. Function
        6.3 GOTO and GOSUB
        6.4 ON ERROR
        6.5 Declaring a subroutine
       6.6 Declaring a function
     7 Arrays and Types
       7.1 Built-in Types
       7.2 User-defined type
       7.3 Array
       7.4 Multidimensional array
       7.5 Non-zero base
     8 Appendix
       8.1 Commands
         8.1.1 ABS()
         8.1.2 ACCESS
         8.1.3 ASC()
         8.1.4 ATN()
         8.1.5 BEEP
         8.1.6 CASE
         8.1.7 CHAIN
         8.1.8 CHDIR
         8.1.9 CHR$()
         8.1.10 CINT()
         8.1.11 CIRCLE
         8.1.12 CLEAR
         8.1.13 CLOSE
         8.1.14 CLS
         8.1.15 COLOR
         8.1.16 COMMON
         8.1.17 CONST
         8.1.18 DATA
         8.1.19 DATE$
         8.1.20 DIM
         8.1.21 DO .. LOOP
         8.1.22 DRAW
         8.1.23 END
         8.1.24 END IF
         8.1.25 ENVIRON
         8.1.26 EOF()
         8.1.27 ERASE
         8.1.28 ERROR
         8.1.29 EXIT
         8.1.30 FOR .. NEXT
         8.1.31 GOSUB
         8.1.32 IF
         8.1.33 INCLUDE
         8.1.34 INKEY$
         8.1.35 INPUT
         8.1.36 INPUT #
         8.1.37 INSTR
         8.1.38 LEFT$()
         8.1.39 LET
         8.1.40 LINE
         8.1.41 LINE INPUT #
         8.1.42 LOADIMAGE
         8.1.43 LOOP
         8.1.44 LPRINT
         8.1.45 MID$
         8.1.46 OPEN
         8.1.47 PALETTE
         8.1.48 READ
         8.1.49 REM or '
         8.1.50 RETURN
         8.1.51 PLAY
            8.1.52 PRINT
            8.1.53 PSET
            8.1.54 SCREEN
            8.1.55 SEEK
            8.1.56 SGN
            8.1.57 SLEEP
            8.1.58 SOUND
            8.1.59 STR$
            8.1.60 SYSTEM
            8.1.61 THEN
            8.1.62 TO
            8.1.63 USING
            8.1.64 VAL()
            8.1.65 WHILE ... WEND
       9 Authors
                                            Text Output [edit]
      Text Output
      Print [edit]
      The text output command is PRINT. This is the command that we will be exploring through this section. PRINT takes a series of arguments. What
      that means is that in QBasic, after typing PRINT (note, for a short cut, just type a question mark '?') a programmer types the things he wants
      displayed and PRINT will display them. The first program will display the words "Hello World" on the screen.
      PRINT [Text to screen]
      1HELLO.BAS [edit]
         PRINT "Hello World"
      Understanding 1HELLO.BAS [edit]
      First, copy everything (in this case, one line, but later programs will be much longer) into a text editor or into QBasic itself and save it as
      '1HELLO.BAS'. Next open it in QBasic (if you are not already there) and press F5. This will run the program. A black screen with the words "Hello
      World" in white on your left hand side of the screen should appear. This is your first QBasic program. Now, Press F5 again. Now there should be
      2 lines saying "Hello World". This is because QBasic does not clear the screen every time a program is run. To change this we will use the
      command CLS, which stands for CLear Screen. We will be looking at some other new concepts in the next program as well.
      2HELLO.BAS [edit]
         PRINT "This line will be erased"
         CLS
         PRINT "Hello";
         PRINT " World",
         PRINT "Hello Jupiter"
         PRINT "Good Bye",,"For";" Now"
         PRINT 1,2,3,4,5
      Commas and Semicolons in PRINT and CLS [edit]
      Here is what the program output should look like:
        Hello World   Hello Jupiter
        Good Bye                    For Now
         1             2             3              4              5
      Addressing 2HELLO.BAS in line order, the first line prints "This line will be erased." to the screen, but in the second line, the CLS command
     clears the screen immediately after, so it will not be seen (technically it flashes at the bottom form columns). "Hello Jupiter" should line up with '2'
     at the bottom. More than one comma can be used in a row. In this example, after "Good Bye" two commas are used to move "For Now" over two
     tab columns. "For Now" should line up with '3'.
     My final statement on this topic is to play around with it. Try using commas and semicolons in a program.
     3HELLO.BAS [edit]
       CLS
       hello$ = "Hello World"
       number = 12
       PRINT hello$, number
     Variables [edit]
     Variables are used to store information. They are like containers. You can put information in them and later change the information to something
     else. In this first example they may not seem very useful but in the next section (Input) they will become very useful.
     In this example we use two types of variables - string variables and numeric variables. A string variable holds words, a string of characters (a
     character is a number, letter or symbol). In this case the characters are letters. A string variable is denoted by ending the name of the variable
     with a dollar sign. The string variable in this program is hello$. What ever you set hello$ equal to will be displayed in the PRINT statement. The
     numeric variable is number. Numeric variables do not have a special ending like string variables.
     4FACE.BAS [edit]
       CLS
       LOCATE 14, 34     'position the left eye
       PRINT "<=>"       'draw the left eye
       LOCATE 14, 43     'position the right eye
       PRINT "<=>"       'draw the right eye
       LOCATE 16, 39     'position the nose
       PRINT "o|o"       'draw the nose
       LOCATE 18, 36     'position the mouth
       PRINT "\_______/" 'draw the mouth
       LOCATE 19, 42     'the bottom
       PRINT "The Face by QBasic"
     Locate statement [edit]
     Locate allows you to position the cursor for the next piece of text output. Contrary to cartesian coordinates which read (X,Y), the locate statement
     is LOCATE Y,X. In this case Y is the distance down from the top of the screen and X is the distance from the left side of the screen. The reason
     that LOCATE does not follow the standard coordinate system is that it is not necessary to include the X portion, you can use the format LOCATE
     Y which just specifies the line to start on.
     5FACE.BAS [edit]
       CLS
       
       LOCATE 14, 34
       COLOR 9
       PRINT "<=>"
       
       LOCATE 14, 43
       PRINT "<=>"
       
       COLOR 11
       LOCATE 16, 39
       PRINT "o|o"
       
       COLOR 4
       LOCATE 18, 36
       PRINT "\_______/"