Updating record in random access file dating guide blog
The first four operations listed above are for both text and random access files. Random access means you can move to any part of a file and read or write data from it without having to read through the entire file.
Years ago, data was stored on large reels of computer tape.
It's a little onerous if you are after performance, so you might limit this to debugging.
This is done using one or more file mode specifiers that are single letters "r", "b", "w", "a" and " " in combination with the other letters.
Both are defined as being size_t which is unsigned integer.
The result of this call is to write count items of the specified size.
Note that with binary files, even though you are writing a string (char *), it does not append any carriage return or line feed characters.
If you want those, you must explicitly include them in the string.