linear data search error query

[gerard@dugdill.com]

So I load this into the BASIC programme and hit Run but just get an error message, "No such variable". Is that supposed to happen? I am trying to test a very basic linear search program for the decision maths course. This one seemed to fit the bill.... kr

DATA FRED,17,BILL,21,ALLISON,21,NOEL,32
DATA JOAN,26,JOHN,19,WENDY,35,ZZZZ,0
REPEAT
READ list$,age
IF list$=name$ THEN PRINT name$,age
UNTIL list$=name$ OR list$="ZZZZ"
IF list$="ZZZZ" PRINT "Name not in list"

[Richard Russell]

So I load this into the BASIC programme and hit Run but just get an error message, "No such variable". Is that supposed to happen?

As far as I can see it's complaining that the variable name$ in this line doesn't exist:

Code: Select all

        IF list$=name$ THEN PRINT name$,age

So to that extent it's "supposed to happen", yes. Is there perhaps some code missing which should be initialising name$?

[gerard@dugdill.com]

I am not sure. I seemed to find the exact program I was looking for when looking through the DATA entry in the keyword section of the help guide manual, excerpt below.


DATA...

The following example program segment reads through a list of names looking for the name in 'name$'. If the name is found, the name and age are printed. If not, an error message is printed.

DATA FRED,17,BILL,21,ALLISON,21,NOEL,32
DATA JOAN,26,JOHN,19,WENDY,35,ZZZZ,0
REPEAT
READ list$,age
IF list$=name$ THEN PRINT name$,age
UNTIL list$=name$ OR list$="ZZZZ"
IF list$="ZZZZ" PRINT "Name not in list"

[Richard Russell]

I seemed to find the exact program I was looking for when looking through the DATA entry in the keyword section of the help guide manual, excerpt below.

Yes, but as it says that's only a program segment to illustrate one use of DATA, not a self-contained program. Like most code examples in the manual, it's not useful on its own but only as part of a larger program. What are you trying to do?

[gerard@dugdill.com]

Run the whole program to search for a particular data item using linear search (and then binary search).

Often hit the no such variable barrier.

)

[Richard Russell]

Run the whole program to search for a particular data item using linear search (and then binary search).

The binary-chop method is described, in flow-chart form, here. I use it quite commonly myself.

[gerard@dugdill.com]

Thanks,