C++

0-Overview

3 min read

🧭 Topic: File & Struct

Quick Overview : Structs and File I/O transform simple scripts into robust applications. Structs introduce the basics of Object-Oriented Programming by allowing you to bundle related data and functions into custom types. Meanwhile, File I/O enables persistent storage, allowing programs to save data, manage configurations, and interact with external systems using sequential or random access. Mastering these concepts is essential for managing complex data structures and ensuring information survives beyond a single program execution

📌 Covered in This Topic

  • What is a struct?

    • Grouping related variables under one name
    • Difference between separate variables vs a structured type

  • Why do we need structs?

    • Modeling real-world entities (Student, Book, Point, Date, etc.)
    • Improving code readability and organization
    • Passing related data together to functions

  • Defining a struct

    • Basic syntax
    • Declaring variables of a struct type
    • Accessing members using the . operator

  • Naming conventions

    • Struct names (PascalCase or camelCase)
    • Member variable names (camelCase / snake_case)

  • Methods (functions) inside structs

    • Member functions
    • Difference between data members and behavior
    • When logic belongs inside the struct vs outside

  • Constructors in structs

    • Default constructor
    • Parameterized constructor
    • Initializing members properly
    • Why constructors are useful

  • Nested structs

    • Structs inside other structs (composition)
    • Modeling “has-a” relationships
    • Why a struct cannot contain itself by value
      • Infinite size problem
    • Using pointers to the same struct type (Node* next)

  • Pointers to structs

    • Creating structs on the heap using new
    • Accessing members with the -> operator
    • Difference between . and ->
    • Common mistakes (dangling pointers, forgetting delete)

  • Passing structs to functions

    • By value
    • By reference
    • By pointer
    • Performance and safety considerations

  • Common examples and use cases

    • Student records
    • Game objects
    • Linked list nodes
    • Configuration or settings data

  • Why do we need files?

    • Data persistence (programs don’t lose data after closing)
    • Saving and loading program state
    • Working with large datasets

  • File streams and buffers

    • ifstream, ofstream, fstream
    • How buffering works (conceptual overview)
    • Difference between console I/O and file I/O

  • Sequential File I/O

    • Opening and closing files
      • File modes (ios::in, ios::out, ios::app, etc.)
    • Checking if a file is open
      • is_open() and error handling
    • Reading from files
      • >> operator
      • getline()
      • Reading line by line
    • Writing to files
      • Overwriting vs appending
      • Formatting output

  • Formatted I/O

    • Using setw(), left, right, setprecision
    • Writing aligned and readable data to files

  • Converting file input

    • Reading strings and converting to numbers
    • stoi, stof, stod, stoll
    • Handling invalid input safely

  • Error handling and debugging

    • Using cerr for error messages
    • Checking stream state (fail(), eof())

  • Reading structured data

    • Reading struct data from files
    • Reading CSV-formatted files
      • Delimiters
      • Parsing lines manually
      • Common pitfalls

  • Random access File I/O

    • Concept of file cursor
    • seekg() and tellg()
    • When random access is useful
    • Limitations and typical use cases

📑 Slides & Materials

🛠️ Workshop & Assignments

🌐 Additional Resources

⏩ Navigation

Tip :

If something doesn’t make sense — don’t stay stuck alone. Ask the TA to clarify it right away. Often, a quick question can save you a lot of time and frustration. Remember: if you’re confused, chances are others are too.

Graph View

Backlinks