String manipulation

[Raghavan]

Hi
I give my input through a file. so in my program i get the path of the file from user and manipulate the data in it. i want to place the output also in a file in the same place as my input file. for example my input file resides here G:\BC\BIN\input.txt i want the output file also in the same place like this G:\BC\BIN\output.txt

[nadroj]

ok it seems you know all the file i/o stuff, correct? it then looks like what you have to do is figure out how to get the path to the input file given, ie everything in the input up to the last slash.

how can you get the last occurrence of a slash (or any character)? read strrchr. after finding out where the last occurrence of a slash is, we know the path.

say the input string was c:\file.txt. the last occurrence of a slash, is at index 2 (ie 3rd character). we can then create another string of size number of characters up to the last slash + length of output filename, in your example this would be 10 + 10 = 20 characters. concatenating the new-found path and your output filename should be easy.

edit: also note its possible you dont have permission to write to a given path. if this is just a homework assignment on your home pc im sure that isnt an issue, though. another thing, make sure you prompt (or simply disallow) to overwrite a file if it already exists, to avoid any silly mistakes.

[Adak]

Hi
I give my input through a file. so in my program i get the path of the file from user and manipulate the data in it. i want to place the output also in a file in the same place as my input file. for example my input file resides here G:\BC\BIN\input.txt i want the output file also in the same place like this G:\BC\BIN\output.txt

It might be easier to just ask the user to put your program and his input file, into the same directory. You're using QuickBasic, right?

A while loop can also find that path, if that's not possible:

i = len(pathWithFilestring$

while (mid$(pathWithFilestring$, i, 1) <> "\")  
   i = i - 1
wend

'Now you have the last backslash in the path, which is also it's last character before the filename.
'getting the rest of the path
path$ = left$(pathWithFilestring$, i)

'now add the filename:
path$ = path$ + "output.txt"

'check it
print path$

It will be 1 based, not zero-based.

That's off the cuff, but you get the idea. If you want more help with it, let me know. I have QuickBasic, still.