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         INTRODUCTION TO HIGH-LEVEL PROGRAMMING (C++)
         PRACTICAL LAB SESSION 9: File Handling
         State University of Zanzibar (SUZA)
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OBJECTIVES:
- Read from and write to text files
- Use ifstream, ofstream, and fstream
- Handle file errors and end-of-file
- Process data stored in files

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PART A: BASIC FILE I/O
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1. Write to File:
   Create a program that writes the following to a file called "output.txt":
   - Your name
   - Your registration number
   - Today's date
   - A message: "I am learning file handling in C++!"

2. Read from File:
   Write a program that reads "output.txt" (from Q1) and displays its
   contents on screen, line by line.

3. Append to File:
   Write a program that appends three additional lines to "output.txt"
   without erasing existing content. Use ios::app mode.

4. Copy File:
   Write a program that reads from "source.txt" and creates an exact
   copy called "backup.txt". Display number of lines copied.

5. File Existence Check:
   Before opening a file, check if it exists. Display appropriate
   error message if file cannot be opened.
   if (!infile.is_open()) { cerr << "Error: cannot open file"; }


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PART B: DATA PROCESSING WITH FILES
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6. Student Records:
   Create a file "students.txt" with the following format:
   Name RegNo Score1 Score2 Score3
   Write a program that:
   a) Reads the file
   b) Calculates average for each student
   c) Writes results to "results.txt" with format:
      Name RegNo Average Grade

7. Number Statistics:
   Create a file with 20 random integers (one per line).
   Write a program that reads the file and calculates:
   - Count of numbers
   - Sum
   - Average
   - Maximum and minimum
   - Count of even and odd numbers

8. Word Frequency:
   Read a text file. Count the frequency of each word.
   Display top 5 most frequent words.

9. Line Counter:
   Write a program that counts:
   - Total lines
   - Blank lines
   - Non-blank lines
   - Total words
   - Total characters


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PART C: STRUCTURED FILE OPERATIONS
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10. Phone Book (File-based):
    Create a simple phone book that stores contacts in a file.
    Operations:
    a) Add contact (name, phone number)
    b) Search by name
    c) Display all contacts
    d) Delete a contact (rewrite file without that contact)

11. Quiz Score Manager:
    Store quiz scores in a CSV file: Name,Q1,Q2,Q3,Q4,Q5
    Implement:
    a) Add student scores
    b) View all scores (formatted table)
    c) Calculate class average per quiz
    d) Find student with highest total

12. Transaction Log:
    Simulate a bank account with file-based transaction log.
    File format per line: TYPE AMOUNT BALANCE DATE
    Operations:
    a) Deposit (append to file)
    b) Withdraw (check balance first, append to file)
    c) View transaction history
    d) Calculate current balance from file


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PART D: EXTRA PRACTICE
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13. [Easy] Count Characters in File
    Read a file and count: letters, digits, spaces, and special characters.

14. [Easy] Uppercase Converter
    Read a text file, convert all text to uppercase, write to new file.

15. [Medium] File Merge
    Given two sorted files (one number per line), merge them into a
    third sorted file.
    file1.txt: 1 3 5 7 9
    file2.txt: 2 4 6 8 10
    merged.txt: 1 2 3 4 5 6 7 8 9 10

16. [Medium] Search and Replace in File
    Read a file, replace all occurrences of a word with another word,
    write the result to a new file.

17. [Medium] CSV Parser
    Read a CSV file with student data:
    Name,Age,GPA
    Ali,20,3.5
    Fatma,21,3.8
    Parse each field and display in a formatted table.

18. [Medium] Inventory System
    File stores: ItemID, ItemName, Quantity, Price
    Implement: Add item, update quantity, calculate total value,
    generate report to file.

19. [Hard] Log File Analyzer
    Read a log file with entries:
    [TIMESTAMP] [LEVEL] Message
    Count entries per level (INFO, WARNING, ERROR).
    Display all ERROR entries.

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TIPS:
- Always close files after use (or use RAII with local scope)
- Check file.is_open() before operations
- Use file.eof() or file.good() for reading loops
- Prefer: while (getline(file, line)) over while (!file.eof())
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