Introduction to C++

Table of Contents

1. •What is C++?
2. •History of C++
3. •Why Learn C++?
4. •C++ Features
5. •C++ vs Other Languages
6. •Setting Up Your Environment
7. •Your First C++ Program
8. •The Compilation Process
9. •Common Terminology
10. •Best Practices for Beginners

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What is C++?

C++ is a general-purpose, high-performance programming language created by Bjarne Stroustrup at Bell Labs in 1979. It was designed as an extension of the C programming language, adding object-oriented features while maintaining C's efficiency and low-level capabilities.

Key Characteristics:

• •Compiled Language: Code is translated directly to machine code for fast execution
• •Statically Typed: Variable types are checked at compile time
• •Multi-paradigm: Supports procedural, object-oriented, and generic programming
• •Low-level Access: Direct memory manipulation through pointers
• •High Performance: Minimal runtime overhead

C++ Name Origin

The name "C++" comes from the increment operator ++ in C, symbolizing that C++ is an "incremented" or enhanced version of C.

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History of C++

Evolution Philosophy

C++ follows a principle of backwards compatibility - older code should continue to work with newer compilers. This has made C++ one of the most stable and long-lasting languages.

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Why Learn C++?

1. Performance Critical Applications

C++ is the language of choice when performance matters:

• •Game Development: Unreal Engine, Unity (core), most AAA games
• •Operating Systems: Windows, macOS, Linux kernels use C/C++
• •Browsers: Chrome, Firefox, Safari rendering engines
• •Databases: MySQL, MongoDB, Redis

2. Industry Demand

Top Industries Using C++:
├── Finance & Trading (High-frequency trading systems)
├── Gaming (Game engines and graphics)
├── Embedded Systems (IoT, automotive, aerospace)
├── System Software (OS, drivers, compilers)
└── Scientific Computing (Simulations, research)

3. Foundation for Other Languages

Understanding C++ helps you learn:

• •How memory actually works
• •How higher-level languages are implemented
• •Performance optimization techniques
• •Computer architecture concepts

4. Career Opportunities

• •Game Developer
• •Systems Programmer
• •Embedded Software Engineer
• •Quantitative Developer
• •Graphics Programmer
• •Compiler Engineer

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C++ Features

Core Language Features

1. Object-Oriented Programming (OOP)

OOP Pillars in C++:
├── Encapsulation - Bundling data with methods
├── Inheritance - Creating new classes from existing ones
├── Polymorphism - Same interface, different implementations
└── Abstraction - Hiding complex implementation details

2. Generic Programming (Templates)

Write code that works with any data type:

template<typename T>
T maximum(T a, T b) {
    return (a > b) ? a : b;
}
// Works with int, double, string, custom types...

3. Memory Management

• •Manual control with new and delete
• •Smart pointers for automatic management (unique_ptr, shared_ptr)
• •Stack vs Heap allocation choices

4. Standard Template Library (STL)

Rich collection of:

• •Containers: vector, list, map, set, queue, stack
• •Algorithms: sort, find, transform, accumulate
• •Iterators: Unified way to traverse containers

Modern C++ Features (C++11 and beyond)

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C++ vs Other Languages

C++ vs C

C++ vs Java

C++ vs Python

C++ vs Rust

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Setting Up Your Environment

Option 1: GCC (GNU Compiler Collection)

Linux (Ubuntu/Debian)

sudo apt update
sudo apt install g++ build-essential

macOS

xcode-select --install
# or install Homebrew, then:
brew install gcc

Windows

• •Install MinGW-w64 or use WSL (Windows Subsystem for Linux)
• •Download from: https://www.mingw-w64.org/

Option 2: Clang

# Linux
sudo apt install clang

# macOS (comes with Xcode)
clang++ --version

Option 3: Visual Studio (Windows)

• •Download Visual Studio Community (free)
• •Select "Desktop development with C++" workload

Recommended IDEs/Editors

Verifying Installation

g++ --version
# Should output something like:
# g++ (Ubuntu 11.4.0-1ubuntu1~22.04) 11.4.0

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Your First C++ Program

The Classic "Hello, World!"

// hello.cpp - Your first C++ program

#include <iostream>  // Include the I/O library

int main() {         // Main function - program entry point
    std::cout << "Hello, World!" << std::endl;
    return 0;        // Return 0 indicates success
}

Breaking It Down

1. Comments

// This is a single-line comment

/* This is a
   multi-line comment */

2. Preprocessor Directive

#include <iostream>

• •#include tells the preprocessor to include a header file
• •<iostream> provides input/output functionality
• •Angle brackets <> indicate a standard library header

3. The Main Function

int main() {
    // Your code here
    return 0;
}

• •Every C++ program must have exactly one main() function
• •int means main returns an integer
• •return 0 signals successful execution
• •return 1 (or non-zero) signals an error

4. Output Statement

std::cout << "Hello, World!" << std::endl;

• •std::cout - Standard character output stream
• •<< - Insertion operator (sends data to stream)
• •std::endl - Ends line and flushes buffer
• •std - Standard namespace

Compiling and Running

# Compile the program
g++ hello.cpp -o hello

# Run the executable
./hello

# Output: Hello, World!

Compilation Flags Explained

g++ -std=c++17 -Wall -Wextra -o program source.cpp

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The Compilation Process

C++ compilation happens in four stages:

Source Code (.cpp)
       │
       ▼
┌─────────────────┐
│  PREPROCESSING  │  → Handles #include, #define, macros
└────────┬────────┘
         │
         ▼
┌─────────────────┐
│   COMPILATION   │  → Converts to assembly code
└────────┬────────┘
         │
         ▼
┌─────────────────┐
│    ASSEMBLY     │  → Converts to object code (.o)
└────────┬────────┘
         │
         ▼
┌─────────────────┐
│    LINKING      │  → Combines object files + libraries
└────────┬────────┘
         │
         ▼
    Executable

Stage 1: Preprocessing

• •Removes comments
• •Expands #include directives (copies header content)
• •Expands macros (#define)
• •Processes conditional compilation (#ifdef, #endif)

# See preprocessor output
g++ -E hello.cpp -o hello.i

Stage 2: Compilation

• •Checks syntax
• •Performs type checking
• •Generates assembly code

# See assembly output
g++ -S hello.cpp -o hello.s

Stage 3: Assembly

• •Converts assembly to machine code
• •Creates object file (.o or .obj)

# Create object file
g++ -c hello.cpp -o hello.o

Stage 4: Linking

• •Combines object files
• •Links library functions (like cout)
• •Creates final executable

# Link object file to create executable
g++ hello.o -o hello

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Common Terminology

Essential Terms

C++ Specific Terms

Memory Terms

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Best Practices for Beginners

1. Always Initialize Variables

// Bad - undefined behavior
int x;
cout << x;  // Who knows what this prints?

// Good - explicitly initialized
int x = 0;
cout << x;  // Prints 0

2. Use Meaningful Names

// Bad
int a, b, c;
double x;

// Good
int studentAge;
int numberOfStudents;
double averageGrade;

3. Enable Compiler Warnings

# Always compile with warnings enabled
g++ -Wall -Wextra -Werror program.cpp

4. Use Modern C++ Features

// Old style
int* ptr = NULL;
for (int i = 0; i < vec.size(); i++) { }

// Modern style
int* ptr = nullptr;
for (const auto& item : vec) { }

5. Comment Your Code

// Calculate the area of a circle
// Formula: A = π * r²
double calculateArea(double radius) {
    const double PI = 3.14159265359;
    return PI * radius * radius;
}

6. Consistent Formatting

Pick a style and stick to it:

// Style 1: K&R / One True Brace Style
if (condition) {
    doSomething();
}

// Style 2: Allman
if (condition)
{
    doSomething();
}

7. Start Simple, Build Up

1. •Write minimal code first
2. •Test it works
3. •Add one feature
4. •Test again
5. •Repeat

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Summary

C++ is a powerful, efficient, and versatile programming language that has stood the test of time. While it has a steeper learning curve than some modern languages, mastering C++ gives you:

• •Deep understanding of how computers work
• •Skills applicable to high-performance computing
• •Foundation for learning other languages
• •Access to a vast ecosystem and job market

Next Steps

1. •✅ Set up your development environment
2. •✅ Write and compile "Hello, World!"
3. •📖 Move on to Syntax and Structure lesson
4. •💻 Practice with the exercises in this module

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Quick Reference Card

Compilation:     g++ -std=c++17 -Wall source.cpp -o program
Run:             ./program
Comments:        // single line    /* multi-line */
Include:         #include <header>
Main:            int main() { return 0; }
Output:          std::cout << "text" << std::endl;
Input:           std::cin >> variable;
Namespace:       using namespace std;  // or use std:: prefix

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Next Lesson: Syntax and Structure