Intel 9800758-02 manual Writing to a Sequential File, Reading from a Sequential File

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Disk File Input/Output

BASIC-SO

String and numeric expressions can replace any of the parameters:

OPEN M$,FN, DN$+ "OUTPUT"

This statement opens a file for either input or output, depending on the value of M$ (it must be either "I" or "0") and assigns the file number represented by FN (it must be from 1 to 6). The name of the file is the value of the string variable DN$ (it should be ":FO:" through ":F9:", depending on how many drives you have, or null) followed by the six characters OUTPUT.

NOTE

Remember that opening a file for output destroys an existing file of the same name.

Writing to a Sequential File

After you open a sequential file for output, you can write data to it with the PRINT statement. If you open an existing file for output, its contents are deleted. To specify that a PRINT statement is being used to write to a sequential disk file, the file number (preceded by #, followed by a comma) follows the word PRINT.

To print a series of constants and variables to file 3:

PRINT #3, "Today'sdate is ";MO$;OA;",";YR

You can also use the full formatting capabilities of the PRINT USING statement:

PRINT #3 USING, "###,##;"234.41 ;81.20;4.68

Refer to Chapter 6 for further details of PRINT USING.

Reading from a Sequential File

After you open a sequential file for input, you can read data from it with the INPUT and LINE INPUT statements. To specify that these statements are being used to read from a sequential disk file, the file number (preceded by # and followed by a comma) follows the word INPUT or LINE INPUT.

The INPUT statement reads the specified number of values (numeric or string) from the disk file. Numeric values (in the disk file) can be separated by a blank, comma, carriage return, or line feed.

String values can be enclosed in quotation marks, or given as unquoted strings. Quoted strings terminate on the quote marks, while unquoted strings terminate on commas, carriage returns, line feeds, or if they exceed 255 characters in length.

Assume, for example, that disk file #2 contains the following data (a new line represents a carriage return-line feed pair in the disk file):

"R1" ,200, "R2" ,2200, "R3" ,10000 "R4" ,.47

After the file is opened for input, the following INPUT statement would assign a string value to R$ and the subsequent numeric value to R:

INPUT #2,R$,R

If executed four times, it would read all eight values.

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Contents BASIC-SO Reference Manual A108/0979/7500 FL Preface Page Contents Illustrations Chapter Introduction to BASIC-80 Invoking BASIC-80Basic filename MEMTOPaddress ExamplesIntroduction to BASIC-80 FilenameChanging File Attributes Listing the Directory of a DiskRenaming a File Deleting a FileYou can now run, list, or edit the program Save LP ,ACommands StatementsBASIC-80 Commands Contd BASIC-80 StatementsBASIC-80 Statements Contd BASIC-80 FunctionsBASIC-80 Functions Contd Representing Data FunctionsDecimal Integer Constants ConstantsInteger Constants Hexadecimal Integer ConstantsSingle-Precision Floating-Point Constants Octal Integer ConstantsDouble-Precision Floating-Point Constants This is a string constant String ConstantsString Variables $ = Enter next data stringL4! = Csng l4 YI,1String Arrays Arithmetic Operators BASIC-SO Operators in Order of Precedence ContdNumeric Expressions Logical OperatorsString Operator String ExpressionsEntering and Editing Programs 30 A=8*52 30 A=8*37 30 A=8*5230 A=8 30 A--=8xx*522537 Control-R a = 8*37Integer D SubcommandCommand 3D press 3, then D results If AB thenIf AB then 120 Else Null SET Syntax of the X subcommand is At this point, the other editing subcommands may be usedMove the cursor to PRINT. Enter 2C RE L Print Undefined SET The E subcommand is enteredInteger C character character Print Undefined SET. Enter a LSyntax Error Messages BASIC-80 Error MessagesOverflow, Underflow, and Divide-by-Zero Error Trapping Trace Facility Restarting Program Execution Error SimulationError Handling If line 40 is replaced withOpening a Sequential File Open 1,#1,F1DATESReading from a Sequential File Refer to for further details of Print UsingWriting to a Sequential File If executed four times, it would read all eight valuesClosing a Sequential File Value of R$ would beDefining a Random 1/0 Field-FIELD BuffersField #3, 20 AS N$ Disk File Input/Output Field #3, 20 AS N$, 9 AS SS$Any of the parameters can be variables Opening and Closing a Random Disk FileReading from a Random 1/0 File To read the next recordSingle-precision value Writing to a Random 1/0 FileInteger Double-precision valueMKI$ Auto first lineJ, increment Attrib Fdrive numberfilename, W1Attrib Fdrive numberfilename, WO Clear expression,addressCommands and Statements CloseDEF FNX Rules for function name are the same as for variable nameDefsng Defdbl Defstr Defint DIM DeleteEdit ErrorDIR ENDField Error expressionExit FOR-NEXT-STEPFor variable=expression to expression Step expression GETGosub GET I file number ,record numberInput IF-THEN-ELSEGoto Line Input KillLET ListLSET, Rset LoadMerge NEWNext 9 16On ... Goto On ... GosubOpen OUT Option BasePoke Print Print UsingString Fields Numeric fields If X$=SEVEN and Y$=EIGHT, the results of line 40 would bePrun PUTRandomize ReadREM Resume ReturnLine number RUN filename SaveRUN line numberlstring expression ,F 60 ENDTRON, Troff ? 5,8,2Wait WidthABS ATNCint CHR$Functions 10 A# = 1.00/3.00 CsngCVI CVS AO/o =Dskf EOFFIX Ok·INP HexsInputs Instr INTLEFT$ LOF LENLOC LOGMKI$ MKS$ MKD$ MID$OCT$ POS integer RightsPeek expression RIGHT$ string,integerSpaces SGNSIN 10 a =1If A$ = 2 then Print Correct Else Goto SPCSPC integer SQRexpressionTAB expression STR$ expressionTAN expression Here is an example of how the USRn statement is used 60 AO/o =Appendix a BASIC-SO Error Codes Table A-I. BASIC-80 Error CodesTable A-I. BASIC-SO Error Codes Contd Appendix B BASIC-SO Reserved Words Page To tab across the line To halt program execution and return to commandLevel To resume program execution after it is stopped byPage Table D-l. Ascii Code List Appendix D Ascii CodesTable D-2. Ascii Code Definition BELAppendixe Calling Subroutines Figure B-1. Internal Representation of Numbers and Strings Some Real Examples RESULT=USR%1VARPTRA, VARPTRB, VARPTRC» PRINTA+B+C= ResultFigure E-2 /8085 Assembly Language Program Figure E-3. PL/M-80 Program Appendix F RMX/SO BASIC-SO Initializing the Predefined RMX/SO BASIC-SO Configuration ISIS-II BASIC-SOTable F-l. Sample Configuration Jumper Wiring OOOOH-OFFFHBASIC-80 Object Files Generating Boot-Loaded and PROM-Based VersionsBASIC-80 Source Files BASIC-80 Executable FilesGenerating a Boot-Loaded RMX/80 BASIC-80 Setting baud rates, refer to the RMX/SO Users Guide That are not boot loadedThis option is used to allocate memory. It is 1 if the boot This option enables your user-written I/O drivers if youISBC 80/20-4 Generating a PROM-Based RMX/80 BASIC-80 Prom F1 RMX820.L1BSTART, & FOBASCM.OBJ,& FORMXBAS.LlB F1 DFSDIR. L1BDIRECTORY ,RENAM E,& F1 MTI810.L1B Configuration Requirements Configuring DFS on an iSBC 80/10Adding BASIC-SO to an Existing RMX/SO Configuration ISBC SO/10 System ClockPublic Variables Adding User-Written I/O Drivers to RMX/SO BASIC-SO Open 0,#1, L1LlSTFigure F-S. Sample User-Written 1/0 Driver Routine Altering BASIC-80 Workspace Burning a BASIC-80 Program Into PromBaprom F1HEATER.BAS Page Index Ase BASIC-80 RIGHT$,7-1O Request for Readerscomments 111111
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