GWBASIC User's Manual

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GW-BASIC User's Guide together in a logical manner to create programs. The GW-BASIC User's Reference describes all of the statements available for use in GW-BASIC. In a GW-BASIC program, lines have the following format: nnnnn statement[statements] nnnnn is a line number statement is a GW-BASIC statement. A GW-BASIC program line always begins with a line number and must contain at least one character, but no more than 255 characters. Line numbers indicate the order in which the program lines are stored in memory, and are also used as references when branching and editing. The program line ends when you press the RETURN key. Depending on the logic of your program, there may be more than one statement on a line. If so, each must be separated by a colon (:). Each of the lines in a program should be preceded by a line number. This number may be any whole integer from 0 to 65529. It is customary to use line numbers such as 10, 20, 30, and 40, in order to leave room for any additional lines that you may wish to include later. Since the computer will run the statements in numerical order, additional lines needn't appear in consecutive order on the screen: for example, if you entered line 35 after line 60, the computer would still run line 35 after line 30 and before line 40. This technique may save your reentering an entire program in order to include one line that you have forgotten. The width of your screen is 80 characters. If your statement exceeds this width, the cursor will wrap to the next screen line automatically. Only when you press the RETURN key will the computer acknowledge the end of the line. Resist the temptation to press RETURN as you approach the edge of the screen (or beyond). The computer will automatically wrap the line for you. You can also press CTRL-RETURN, which causes the cursor to move to the beginning of the next screen line without actually entering the line. When you press RETURN, the entire logical line is passed to GW-BASIC for storage in the program. In GW-BASIC, any line of text that begins with a numeric character is considered a program line and is processed in one of three ways after the RETURN key is pressed: ● A new line is added to the program. This occurs if the line number is legal (within the range of 0 through 65529), and if at least one alpha or special character follows the line number in the line. ● An existing line is modified. This occurs if the line number matches the line number of an existing line in the program. The existing line is replaced with the text of the newlyentered line. This process is called editing. file:///C|/Documents%20and%20Settings/Lorenzo/Desktop/GW%20Basic/Chapter%202.html (7 of 8)28/03/2004 21.28.57
GW-BASIC User's Guide Note Reuse of an existing line number causes all of the information contained in the original line to be lost. Be careful when entering numbers in the indirect mode. You may erase some program lines by accident. ● An existing line is deleted. This occurs if the line number matches the line number of an existing line, and the entered line contains only a line number. If an attempt is made to delete a nonexistent line, an "Undefined line number" error message is displayed. 2.6 Returning to MS-DOS Before you return to MS-DOS, you must save the work you have entered under GW-BASIC, or the work will be lost. To return to MS-DOS, type the following after the Ok prompt, and press RETURN: system The system returns to MS-DOS, and the A> prompt appears on your screen. file:///C|/Documents%20and%20Settings/Lorenzo/Desktop/GW%20Basic/Chapter%202.html (8 of 8)28/03/2004 21.28.57
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GW-BASIC User's Guide The program i
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GW-BASIC User's Guide PUT #1, CODE%
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GW-BASIC User's Guide number. Lines
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GW-BASIC User's Guide Appendix A Er
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GW-BASIC User's Guide 18 Undefined
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GW-BASIC User's Guide 59-60Unprinta
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GW-BASIC User's Guide 75 Path/File
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GW-BASIC User's Guide Appendix C AS
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GW-BASIC User's Guide Appendix D As
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GW-BASIC User's Guide moved the cur
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GW-BASIC User's Guide that the code
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GW-BASIC User's Guide converted to
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GW-BASIC User's Guide DEF USR State
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GW-BASIC User's Guide USR Function
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GW-BASIC User's Guide E.3 Multiple
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GW-BASIC User's Guide 8 8 18 24 90
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GW-BASIC User's Guide _ Underscore.
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GW-BASIC User's Guide Data represen
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GW-BASIC User's Guide binary system
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GW-BASIC User's Guide computers or
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GW-BASIC User's Guide double-precis
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GW-BASIC User's Guide graphics A ha
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GW-BASIC User's Guide precisely ref
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GW-BASIC User's Guide An extra-bit
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GW-BASIC User's Guide single-densit
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GW-BASIC User's Guide ABS Function
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GW-BASIC User's Guide CHR$ Function
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GW-BASIC User's Guide AUTO Command
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GW-BASIC User's Guide BLOAD Command
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GW-BASIC User's Guide BSAVE Command
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GW-BASIC User's Guide Note ● Valu
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GW-BASIC User's Guide CDBL Function
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GW-BASIC User's Guide INT Function
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GW-BASIC User's Guide CHAIN Stateme
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GW-BASIC User's Guide MERGE Command
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GW-BASIC User's Guide CIRCLE Statem
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GW-BASIC User's Guide COLOR Stateme
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GW-BASIC User's Guide For more info
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GW-BASIC User's Guide EGA with Enha
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GW-BASIC User's Guide SCREEN 10 ●
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GW-BASIC User's Guide For various s
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GW-BASIC User's Guide PALETTE, PALE
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GW-BASIC User's Guide Enhanced d EG
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GW-BASIC User's Guide N Move, but r
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GW-BASIC User's Guide LINE Statemen
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GW-BASIC User's Guide LINE (0,0)-(1
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GW-BASIC User's Guide tile_length i
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GW-BASIC User's Guide PRESET and PS
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GW-BASIC User's Guide CLEAR Command
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GW-BASIC User's Guide CLOSE Stateme
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GW-BASIC User's Guide COM(n) Statem
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GW-BASIC User's Guide CONT Command
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GW-BASIC User's Guide CSRLIN Variab
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GW-BASIC User's Guide CVI, CVS, CVD
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GW-BASIC User's Guide DATA Statemen
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GW-BASIC User's Guide RESTORE State
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GW-BASIC User's Guide the value of
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GW-BASIC User's Guide DEFINT/SNG/DB
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GW-BASIC User's Guide DEF and SEG m
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GW-BASIC User's Guide POKE Statemen
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GW-BASIC User's Guide EDIT Command
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GW-BASIC User's Guide ENVIRON State
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GW-BASIC User's Guide ENVIRON$ Func
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GW-BASIC User's Guide SHELL Stateme
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GW-BASIC User's Guide EOF Function
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GW-BASIC User's Guide ERDEV and ERD
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GW-BASIC User's Guide ERROR Stateme
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GW-BASIC User's Guide EXP Function
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GW-BASIC User's Guide FIELD Stateme
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GW-BASIC User's Guide GET Statement
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GW-BASIC User's Guide FOR ... NEXT
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GW-BASIC User's Guide FRE Function
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GW-BASIC User's Guide The number of
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GW-BASIC User's Guide GOTO Statemen
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GW-BASIC User's Guide OCT$ Function
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GW-BASIC User's Guide Testing Equal
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GW-BASIC User's Guide 1070 TIMEOUT%
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GW-BASIC User's Guide INPUT Stateme
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GW-BASIC User's Guide PRINT Stateme
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GW-BASIC User's Guide STRING$ Funct
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GW-BASIC User's Guide PRINT USING S
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GW-BASIC User's Guide ** A double a
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GW-BASIC User's Guide WIDTH Stateme
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GW-BASIC User's Guide INPUT# Statem
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GW-BASIC User's Guide 100 PRINT "TY
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GW-BASIC User's Guide IOCTL Stateme
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GW-BASIC User's Guide KILL Command
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GW-BASIC User's Guide MID$ Function
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GW-BASIC User's Guide LEN FUNCTION
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GW-BASIC User's Guide LINE INPUT# S
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GW-BASIC User's Guide LLIST Command
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GW-BASIC User's Guide LOC Function
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GW-BASIC User's Guide Makes the cur
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GW-BASIC User's Guide It is expecte
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GW-BASIC User's Guide LOG Function
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GW-BASIC User's Guide MID$ Statemen
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GW-BASIC User's Guide NAME Command
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GW-BASIC User's Guide ON ERROR GOTO
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GW-BASIC User's Guide ON ... GOSUB
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GW-BASIC User's Guide reclen is an
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GW-BASIC User's Guide ● Files may
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GW-BASIC User's Guide RESET Command
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GW-BASIC User's Guide Examples: The
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GW-BASIC User's Guide when using GE
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GW-BASIC User's Guide PCOPY Command
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GW-BASIC User's Guide n = 5 Returns
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GW-BASIC User's Guide . (period) A
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GW-BASIC User's Guide PMAP Function
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GW-BASIC User's Guide The following
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GW-BASIC User's Guide If the string
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GW-BASIC User's Guide PUT Statement
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GW-BASIC User's Guide RANDOMIZE Sta
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GW-BASIC User's Guide RND Function
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GW-BASIC User's Guide . . . 129 FOR
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GW-BASIC User's Guide RESUME Statem
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GW-BASIC User's Guide RMDIR Command
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GW-BASIC User's Guide SAVE Command
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GW-BASIC User's Guide SGN Function
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GW-BASIC User's Guide SOUND Stateme
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GW-BASIC User's Guide SPACE$ Functi
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GW-BASIC User's Guide SQR Function
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GW-BASIC User's Guide STOP Statemen
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GW-BASIC User's Guide VAL Function
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GW-BASIC User's Guide STRIG(n) Stat
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GW-BASIC User's Guide SYSTEM Comman
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GW-BASIC User's Guide TAN Function
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GW-BASIC User's Guide 08:00:05 The
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GW-BASIC User's Guide TRON/TROFF Co
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GW-BASIC User's Guide 0 1 Mode The
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GW-BASIC User's Guide VARPTR$ Funct
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GW-BASIC User's Guide The following
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GW-BASIC User's Guide WAIT Statemen
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GW-BASIC User's Guide WINDOW Statem
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GW-BASIC User's Guide WRITE Stateme
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