📁 File Handling¶

Prerequisites: None

Programs lose their data once they stop running. File handling allows you to store data permanently on your hard drive.

1. Create and Write¶

Rating: Beginner | Difficulty: Easy Create a new file named test.txt and write "Hello Files!" into it.

💡 Hint

Use fopen with "w" mode in C, ofstream in C++, or FileWriter in Java.

2. Read and Display¶

Rating: Beginner | Difficulty: Easy Read the contents of test.txt and print them to the console.

💡 Hint

Use a loop to read until the end of the file (EOF).

3. Append Content¶

Rating: Beginner | Difficulty: Easy Open an existing file and add a new line at the end without deleting existing data.

💡 Hint

Use the "append" mode ("a" in C or FileWriter(file, true) in Java).

4. Character Count¶

Rating: Beginner | Difficulty: Easy Read a file and count how many characters it contains.

💡 Hint

Increment a counter for every character read from the file.

5. Line Count¶

Rating: Intermediate | Difficulty: Medium Count how many lines of text are in a file.

💡 Hint

Count the number of newline characters (\n).

6. Copy File¶

Rating: Intermediate | Difficulty: Medium Read data from source.txt and write it into a new file destination.txt.

💡 Hint

Read one character/line at a time and immediately write it to the second file.

7. Search for a Word¶

Rating: Intermediate | Difficulty: Medium Ask the user for a word and check if it exists inside a specific file.

💡 Hint

Read the file word by word and use string comparison.

8. Word Frequency¶

Rating: Advanced | Difficulty: Hard Find how many times a specific word appears in a text file.

💡 Hint

Similar to search, but keep a counter instead of stopping at the first match.

9. Replace Word¶

Rating: Advanced | Difficulty: Hard Search for "oldWord" in a file and replace every occurrence with "newWord".

💡 Hint

Read from the source file, modify the strings in memory, and write to a temporary file. Then rename the temp file.

10. Merge Two Files¶

Rating: Intermediate | Difficulty: Medium Read contents from two different files and combine them into a third file.

💡 Hint

Copy file 1, then copy file 2 into the target file.

11. Student Records (Binary)¶

Rating: Advanced | Difficulty: Medium Store student data (Name, Roll No, Marks) into a binary file.

💡 Hint

Use struct in C/C++ or Serializable objects in Java.

12. List Files in Directory¶

Rating: Pro | Difficulty: Hard Write a program that prints the names of all files in the current folder.

💡 Hint

Requires system-level libraries like dirent.h in C or java.io.File in Java.

13. Read CSV and Calculate¶

Rating: Advanced | Difficulty: Medium Read a .csv file containing prices and calculate the total sum.

💡 Hint

Split each line by the comma , delimiter.

14. Reverse File Content¶

Rating: Pro | Difficulty: Hard Read a file and write its contents in reverse order into another file.

💡 Hint

Read everything into a large buffer/list first, then write it out backwards.

15. Simple Logger¶

Rating: Intermediate | Difficulty: Medium Create a function logMessage(msg) that appends the current date/time and the message to a log.txt file.

💡 Hint

Useful for debugging real applications!

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