C File Handling

What is File Handling?

File handling allows programs to read from and write to files on disk.

This is useful for saving data, logs, and configurations.

File Pointer

A file is handled using a FILE pointer.

Opening a File

Use fopen() to open a file.

It returns a pointer to the file.

File Modes

Common file modes include:

• "r" – read
• "w" – write (overwrite)
• "a" – append

Closing a File

Always close files after use to free resources.

Writing to a File

Use fprintf() to write formatted data to a file.

Reading from a File

Use fscanf() or fgets() to read data.

Reading Character by Character

You can read one character at a time using fgetc().

Checking File Errors

Always check if the file opened successfully.

Appending to a File

Use append mode to add data without overwriting existing content.

Real-World Example

Writing and reading from a file in one program.

Why File Handling is Important

File handling is used in many real-world applications.

• Saving data
• Reading configuration files
• Logging program output

Common Mistakes

Be careful with these:

• Forgetting to close files
• Not checking NULL pointer
• Using wrong file mode

Practice

Write a program that writes text to a file and then reads and prints it.

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