Commodore Plus 4 - Page 339

The Disk Drive 327
Example: 10 0PEin,8,2,"DATAFILE,S,W"
20 IFDSO0THENPRIlTTDS$:CL0SEl:E]SrD
30 F0RI=lT010
40 PRINT''WHAT ARE'T'TH VALUES OF X AM) Y'^:IIIPUTX,Y
50 PRIlTT#l,X;//,//;Y
60 IFDS=OTHENNEXT:ELSEPRIHTDS$:CLOSEl:E]SrD
70 CL0SE1
80 0PEEU,8,2,"DATAFILE"
90 1=1
100 INPUT#1,X,Y
110 PRINT I"TH VALUES ARE",X,Y
120 IFST=OTHENT=I+1:GOTO1OO
130 CL0SE1
Line-by-Line Explanation
10 Open a sequential file called DATAFILE on device 8 using channel 2 for
writing.
20 Check for an error. If one is found, print message and stop.
30 I runs from 1 to 10.
40 Accept input from the keyboard for the values of X and Y.
50 Output the values of X and Y to the data file separated by a comma. A
carriage return is automatically sent because no semicolon is found at the
end of the statement.
60 Check for an error. If there is no error, get next I. If there is an error,
print message and stop.
70 Close the data file just created.
80 Now, open DATAFILE for reading. Since the type and mode are omit
ted, they are assumed to be sequential and read.
90 I counts the records read.
100 Read a set of X and Y.
110 Print the values read.
120 Check for end-of-file. If not found, add one to I and read next record.
130 Close the file.