Programming Techniques DT143G

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary purpose of using files in programming?

To save data for later use (correct)

To enhance visual interface design

To generate random numbers

To increase execution speed of programs

Which of the following file modes allows both reading and writing to a file without truncating it?

r+ (correct)

What steps should be followed to properly handle files in programming?

Open, read, write, and close

Create, edit, and close

Read, write, and save

Open, use, and close (correct)

What will fopen return if it fails to open a file?

NULL Signup and view all the answers

Which file type is considered not human-readable?

Binary files Signup and view all the answers

What is a potential risk when opening files?

Data could be deleted if not closed properly Signup and view all the answers

In the fopen function, what does the 'a' mode signify?

Append data to the end of a file Signup and view all the answers

Which programming construct is utilized to write text to a file in the provided example?

fprintf Signup and view all the answers

What must be done after finishing file operations in C programming to ensure no data is lost?

Call fclose Signup and view all the answers

What is the main difference between reading from a text file and a binary file in C?

Binary files allow for more complex data structures Signup and view all the answers

What function can be used to read a line from a file in C?

fgets Signup and view all the answers

In the code example provided, what happens if myfile is NULL?

An error message is printed, and the program exits Signup and view all the answers

Why is it important to check for EOF when reading a file?

To prevent reading beyond the end of the file Signup and view all the answers

When appending data to a file, which operation should be considered?

Create a temporary file to handle the original Signup and view all the answers

What is a potential risk when writing data to a file?

Data being overwritten or deleted unintentionally Signup and view all the answers

What does the function sscanf do in the context of file reading?

It reads a formatted string from another string Signup and view all the answers

Study Notes

Programmeringsteknik DT143G - Lecture 8: Files

Lecture Date: December 2nd, 2024
Lecturer: Pascal Rebreyend
Topic: File Handling in Programming

File Types

Text Files:
- Human-readable.
- Examples include .c files, log files, and configuration files.
- Each character represented by a single byte.
Binary Files:
- Not human-readable.
- Examples include executable files, images, and videos.
- Data stored in a format that's not directly interpretable by humans.

File Operations

Opening a File:
- Use fopen to open a file.
- Supply the filename and mode (e.g., "r" for reading, "w" for writing, "a" for appending).
- The fopen function returns a file pointer (FILE *).
- Crucial to close the file (fclose) to free resources after use.

File Operations - Reading & Writing

Reading:
- Use fscanf for formatted input from a file.
- Use fgets for reading entire lines from a file.
Writing:
Use fprintf for formatted output to a file.
Use caution when writing (e.g., avoid overwriting data intentionally if the mode is not append "a").
Data Handling:
- Be mindful of file formats (e.g., UTF-8, ASCII).
- Check for errors using the returned value of fopen.
- The function fclose releases resources occupied by the file.

File Structure

Sequential Data Handling:
- Reading and writing data line by line can be efficient for text files (e.g. fgets).
- The order in which the data is accessed is important and directly related to how it's stored on disk.

Closing Files

Important: Always close the file using fclose to ensure data is written to disk and prevent data loss. Error checking is important.

Reading by Line

fgets: Useful for reading lines of a text file.

Complex File Operations

Modifying files is typically achieved by creating a temporary file in which the necessary changes are built before overwriting/copying to the original file.

File Handling Summary

Purpose: Files store data persistently on a disk, providing a way for programs to interact with external information.
Process: Files are opened, used for reading/writing, and closed.
Caution: Proper file handling prevents data loss and accidental overwriting.
Mode: Choosing the correct mode ("r," "w," or "a") is crucial for successfully opening and using the file.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Explore the key concepts of file handling in programming from Lecture 8 of the DT143G course. Learn about various file types, operations for opening, reading, and writing files, and the importance of properly managing file resources. This quiz will enhance your understanding of handling files in programming languages.