Chapter 14: File Handling in C

Definition: A logical interface to a file is known as a stream. It is a flow of data.

• Text Stream: Sequence of characters. Character translations (like newline) may occur. No one-to-one correspondence with external device bytes.
• Binary Stream: Sequence of bytes. No translation occurs. One-to-one correspondence with external device bytes. More efficient than text streams.

• Sequential Access: Data is accessed in the same sequence as it is stored. Simple but slow for large files.
• Random Access: Data can be accessed directly without reading preceding data. Fast and efficient for searching.

Opening a File (fopen): Associates a file with a stream. Syntax: FILE *fp = fopen("filename", "mode");

Closing a File (fclose): Disconnects the file from the program. Syntax: fclose(fp);

Modes:

• "r": Read only (file must exist).
• "w": Write only (creates new or overwrites existing).
• "a": Append (adds to end, creates if not exists).
• "r+": Read/Write (file must exist).
• "w+": Read/Write (overwrites/creates).
• "a+": Read/Append.

• Character I/O: fgetc() (read char), fputc() (write char).
• String I/O: fgets() (read string), fputs() (write string).
• Formatted I/O: fscanf() (read formatted data), fprintf() (write formatted data).

• EOF (End of File): Special marker indicating the end of data in a file.
• File Pointer: A pointer of type FILE that points to the information required to manage a file.