Hi everybody! I need to write at the beginning of a file that already has a content and I want to insert in it without overwriting what it already contains. Do you know any function to do this? I'm working with streams, by the way, so I need a function that works with ofstreams. Thanks a lot!
Make a new file. Add the line at the beginning. Read the old file and write its contents to the new file. Close the new file. Rename the new file with the old file's name.
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There is no insert text function, you have to do it yourself
Open a new file
Write the data you want at the start of the file
Copy the contents of the old file to the new file.
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I've already thought about it but unfortunately I'm not allowed to use any other file (it's one of the restrictions of the exercise). Anyway, I think I can do it another way. Thanks!
If you can only use one file, you could read all the data in, truncuate the file, and then write all the data (including the new line at the beginning) back to the file. You shouldn't do this in practise; rather, you should do as Salem suggested, otherwise you program might be interrupted while writing the data out, causing data loss. But if your requirement is one file, then do so.
IMHO that's a silly restriction.
dwk
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Thanks! Although I've thought of another way to solve the exercise without doing the file thingy. Thanks a lot anyway!
I totally agree.IMHO that's a silly restriction
What would that be? I dont see how you can work with files without working with filesAlthough I've thought of another way to solve the exercise without doing the file thingy.
Look up a C++ Reference and learn How To Ask Questions The Smart WayOriginally Posted by Bjarne Stroustrup (2000-10-14)
Couldn't he read the whole file into memory, then add what he wants to read to the string, or whatever, then write it all back, overwriting what was there originally?
That was what pretty much what dwks suggested.Couldn't he read the whole file into memory, then add what he wants to read to the string, or whatever, then write it all back, overwriting what was there originally?
Look up a C++ Reference and learn How To Ask Questions The Smart Way
Good point ... wasn't paying attention.
It requires a really long explanation... It's just that I can avoid using the file in question if I approach the exercise in a really different way. It doesn't have anything to do with my original question, so you'd have to know what the entire exercise is about to get it, if you know what I mean... SorryWhat would that be? I dont see how you can work with files without working with files
