File IO: Text vs Binary Files

File Input/Output (IO)

• File IO involves the transfer of data between secondary memory (hard disk) and main memory.

Text and Binary Files

• Text files are human-readable, storing data in terms of text.
• Binary files are not human-readable, storing data in terms of 0s and 1s.
• In text files, newline (\n) characters are converted into carriage return-linefeed combinations before being written to disk.
• In binary files, these conversions do not take place.
• Text files use a special character (ASCII value 26) to mark the end of the file, which is not present in binary mode files.
• In text files, text and characters are stored one character per byte, whereas in binary files, data is stored in its original format.

File Opening

• A file must be opened before reading from or writing to it.
• ofstream or fstream objects can be used to open a file for writing, while ifstream objects are used for reading.
• A file can be opened in different modes for read and write operations.

File Management

• External mass storage media, such as hard disks, are block-oriented, transferring data in blocks of 512 bytes or multiples thereof.
• Efficient file management involves storing data in a temporary storage in main memory, known as a file buffer.
• A file is simply a long byte array from the viewpoint of a C++ program.
• Each character in a file occupies a byte position, with the first byte at position 0.

File Access

• The current file position is the position of the byte that will be read or written next.
• Each byte transferred automatically increases the current file position by 1.
• In sequential access, data is read or written byte by byte in a fixed order.
• Write operations can create a new file, overwrite an existing file, or append new data to an existing file.
• Easy access to given data in a file requires setting the current file position as required.

Streams and Files

• Files are a means to store data in a storage device.
• C++ file handling provides a mechanism to store output of a program in a file and read from a file on the disk.
• Streams refer to a sequence of bytes.
• Files store data.