read-write to binary file

[chippybippy]

I lost my qbasic book
I want to open a binary file
find a certain string
then insert a qbasic generated number to that string
my program generates the numbers
I need to replace old numbers with them
these numbers would be in specific pixal points if needed the line is partial text with my number to be inserted within
? thanx
chip

 

[Buff1]

'one way as long as the file is not too awfully large
open "mybin.fil" for binary as #1
a$=space$(lof(1))
Get #1,,a$
L%=instr(a$,certain.string$)
if L% then
b$=mid$(a$,1,L%-1)+"123"+mid$(a$,L%+1)
else
b$=a$
end if
close #1
open "mybin.fil" for output as #1
print #1,b$;
close #1