How to edit a file or add sometrhing at a specifiede locatioon in a file?

[inciguleray]

I want to knw that how to edit a file? how to delete a whole file? how to add some text at a specified location in a file ? how to delete something from a specified location in a file?

[Banfa]

Are you using C or C++?
What test programs have you written to try out file access and modification?

As a start you will want to be able to open and read the contents of files.