File Handling in C Programming

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Questions and Answers

What is the purpose of a preprocessor directive in C?

It handles memory allocation during execution.

It provides instructions to the compiler before actual compilation. (correct)

It executes code during runtime.

It defines the structure of data files.

What is the difference between text files and binary files?

Text files are typically slower to access compared to binary files. (correct)

Text files have larger sizes due to compression.

Binary files are more human-readable than text files.

Binary files usually contain text data in encoded format.

What does the ftell() function return in C?

The size of the file opened.

The total number of bytes in the file.

The next available byte to write in the file.

The current position of the file pointer in bytes. (correct)

What does the fseek function do when provided with SEEK_END?

Moves the file pointer to a specific location from the end of the file. (D) Signup and view all the answers

Which of the following statements about #ifdef and #ifndef is true?

#ifdef checks if a macro is defined while #ifndef checks if a macro is not defined. (A) Signup and view all the answers

What happens after the rewind() function is called on a file pointer in C?

The file pointer resets to the beginning of the file. (C) Signup and view all the answers

In the provided code, what will be printed after the #undef VALUE statement?

This won't print as VALUE is undefined. (C) Signup and view all the answers

Which statement correctly describes the behavior of the #include directive?

It allows access to functions defined in other files. (A) Signup and view all the answers

What does the fseek() function do in a file handling context?

Moves the file pointer to a specified location. (A) Signup and view all the answers

In the context of copying file content, what is checked immediately after opening the files?

If the files were opened successfully. (A) Signup and view all the answers

How does the program read characters from the source file during the copy operation?

Using the fgetc() function. (A) Signup and view all the answers

What is the purpose of the #define directive in a C program?

To define macros or constants. (B) Signup and view all the answers

What will happen if the source or destination files fail to open?

An error message will be printed and the program will return 1. (A) Signup and view all the answers

In the preprocessor directives, what does #pragma do?

Specifies compiler-specific instructions. (C) Signup and view all the answers

In the program that reads a specified number of records from a file, what method is incorrectly used to read a line from the file?

fgetc() is used to read one character at a time. (D) Signup and view all the answers

What is the significance of the buffer variable in the example that reads 10 bytes from the file?

It must be declared as an array to hold multiple characters. (A) Signup and view all the answers

Study Notes

Preprocessor Directives

Instructions processed before compilation.
Begin with a #.
Used for including files, defining constants, and conditional compilation.

File Types

Text Files: Store data in a readable format (e.g., ".txt").
Binary Files: Store data in binary format. More efficient but not human-readable (e.g., images, executables).

File Handling Functions (fseek, ftell, rewind)

fseek(FILE *stream, long offset, int origin): Moves the file pointer.
- offset: Number of bytes to move.
- origin: Where to start the count (SEEK_SET, SEEK_CUR, SEEK_END).
ftell(FILE *stream): Returns the current position of the file pointer.
rewind(FILE *stream): Resets the file pointer to the beginning of the file.

Text vs. Binary Files

Feature	Text Files	Binary Files
Data Storage	Human-readable	Binary format
File Size	Larger (due to encoding)	Smaller
Access	Slower (parsing required)	Faster
Usage	Logs, config files	Images, executables

File Handling Example (ftell, fseek, rewind)

Demonstrates moving and resetting file pointers.
Shows how fseek moves 10 bytes from the start, ftell reports the new position.
rewind returns to the beginning.

Conditional Compilation (#ifdef, #ifndef, #undef)

Allows selective code compilation based on macro definitions.
#ifdef: Compiles code if the macro is defined.
#ifndef: Compiles code if the macro is not defined.
#undef: Removes the definition of a macro.
Example shows these directives in a program.

ftell Function

Returns the current position (byte offset from the beginning) of a file's pointer.
Used to keep track of where you are in a file for random access.

File Copying Program

Copies the contents of one file to another.
Uses fgetc and fputc for character-by-character copying, handling end-of-file.

fseek for Random Access

fseek enables access to any part of a file by positioning the file pointer.
Allows precise byte reading from various points in a file.

Preprocessor Directives (Detailed)

Executed before compilation.
#include: Includes other files into the source code.
#define: Defines macros (e.g., constants or text replacements).
#undef: Removes a macro definition.
#ifdef/#ifndef: Use conditional compilation to include/exclude code based on predefined macros.
#pragma: Provides compiler-specific instructions.

Printing Specific Records from a File

Reads a specified amount of records from the beginning of a given text file.
Demonstrates file reading to print a specified number of records from the start of a file.
Uses fgets to read lines from the file and prints them until the desired number of records is reached.

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Description

This quiz covers the fundamentals of file handling in C programming, including preprocessor directives and the differences between text and binary files. Assess your understanding of key file handling functions like fseek, ftell, and rewind, and their applications in programming.