deleting the content of a text file

[NatMinx]

Ok... here's my problem:
I have 2 files File1 & File2 in the current dir.

File1:        File2:        tempFile:
20            40            20
30                          30
40

My program is supposed to check if File2's content exists in File1 and delete it.

The way I'm approaching it is:
1) I check if File2's content exists in File1.
2) Then I create a tempFile and append to it everything in File1 but 40(which is File2's content).
3) Now I want to over-write File1's content with tempFile's content, but I'll end up with 20 30 40 again...

My question is, is it possible to completely delete File1's content so that I can easily just write tempFile's content into File1? If so, how? If not, what other option do I have?

Thanx in advance!

 

[cpjust]

Most file I/O is OS specific except for a few standard C functions like fopen(), fread(), fwrite()...

http://www.cppreference.com/stdio/index.html

I belive the only way to truncate a file is by using a platform API call.

What OS are you using?

You could also delete File1 and rename the tempfile to File1.

 

[xwb]

You could open the file for writing, write a blank line to it and then close it. Works on most OSs except VAX/VMS.