C++

A high-performance, systems-level language for applications, game engines, embedded systems, and performance-critical software.

Getting Started

C++ is a compiled, high-performance programming language that builds on C while adding object-oriented, generic, and modern programming features. It is widely used in operating systems, game engines, desktop applications, embedded systems, and high-throughput infrastructure.

Installation

You can install a C++ toolchain using Visual Studio Build Tools on Windows, GCC or Clang on Linux, and Xcode Command Line Tools on macOS.

bash

# Check that your compiler is installed
g++ --version

# Compile and run a program
g++ hello.cpp -o hello
./hello

Hello World

cpp

#include <iostream>

int main() {
    std::cout << "Hello, C++!" << std::endl;
    return 0;
}

Variables & Data Types

C++ is a statically typed language, which means the type of each variable is checked at compile time.

Fundamental Types

cpp

int age = 25;
double price = 19.99;
char grade = 'A';
bool isReady = true;
std::string name = "Alice";

Type Modifiers

cpp

short smallValue = 10;
long long bigNumber = 1234567890123LL;
unsigned int positiveOnly = 42;

Auto Keyword

cpp

auto count = 10;         // int
auto pi = 3.14159;       // double
auto message = std::string("Hello");

Input, Output & Strings

Standard Output

cpp

#include <iostream>
#include <string>

int main() {
    std::string name = "Ada";
    std::cout << "Hello, " << name << "!" << std::endl;
    return 0;
}

String Operations

cpp

#include <string>
#include <iostream>

int main() {
    std::string greeting = "Hello";
    greeting += " world";

    std::cout << greeting << std::endl;   // Hello world
    std::cout << greeting.size() << std::endl;
    return 0;
}

Control Flow

If / Else

cpp

int score = 85;

if (score >= 90) {
    std::cout << "Excellent";
} else if (score >= 70) {
    std::cout << "Good";
} else {
    std::cout << "Try again";
}

Loops

cpp

for (int i = 0; i < 5; ++i) {
    std::cout << i << " ";
}

int count = 0;
while (count < 3) {
    std::cout << count << " ";
    ++count;
}

Switch

cpp

int day = 2;

switch (day) {
    case 1:
        std::cout << "Monday";
        break;
    case 2:
        std::cout << "Tuesday";
        break;
    default:
        std::cout << "Other day";
        break;
}

Functions

Functions help organize logic into reusable blocks of code.

cpp

int add(int a, int b) {
    return a + b;
}

int main() {
    std::cout << add(3, 4) << std::endl; // 7
    return 0;
}

Default Arguments

cpp

void greet(const std::string& name, const std::string& prefix = "Hello") {
    std::cout << prefix << ", " << name << "!" << std::endl;
}

Pass by Reference

cpp

void increment(int& value) {
    ++value;
}

int main() {
    int x = 5;
    increment(x);
    std::cout << x << std::endl; // 6
    return 0;
}

Classes & Object-Oriented Programming

C++ supports classes, constructors, encapsulation, and inheritance.

cpp

#include <iostream>
#include <string>

class Person {
public:
    Person(std::string name) : name(name) {}

    void introduce() const {
        std::cout << "Hi, I am " << name << std::endl;
    }

private:
    std::string name;
};

int main() {
    Person p("Alice");
    p.introduce();
    return 0;
}

Inheritance

cpp

class Animal {
public:
    virtual void speak() const {
        std::cout << "Animal sound" << std::endl;
    }
};

class Dog : public Animal {
public:
    void speak() const override {
        std::cout << "Woof" << std::endl;
    }
};

Standard Template Library (STL)

The STL provides containers and algorithms that make common tasks easier and safer.

Vectors

cpp

#include <vector>
#include <iostream>

int main() {
    std::vector<int> numbers = {1, 2, 3, 4};
    numbers.push_back(5);

    for (int n : numbers) {
        std::cout << n << " ";
    }

    return 0;
}

Maps

cpp

#include <map>
#include <string>
#include <iostream>

int main() {
    std::map<std::string, int> ages;
    ages["Alice"] = 30;
    ages["Bob"] = 25;

    std::cout << ages["Alice"] << std::endl;
    return 0;
}

Algorithms

cpp

#include <algorithm>
#include <vector>
#include <iostream>

int main() {
    std::vector<int> values = {4, 1, 3, 2};
    std::sort(values.begin(), values.end());

    for (int v : values) {
        std::cout << v << " ";
    }

    return 0;
}

Memory & Pointers

Pointers allow direct access to memory. Use them carefully, especially in performance-sensitive code.

cpp

int value = 42;
int* ptr = &value;

std::cout << *ptr << std::endl; // 42

Smart Pointers

cpp

#include <memory>
#include <iostream>

int main() {
    std::unique_ptr<int> ptr = std::make_unique<int>(10);
    std::cout << *ptr << std::endl;
    return 0;
}

Modern C++ Best Practices

Prefer std::string over C-style strings.
Use auto when the type is obvious and improves readability.
Prefer const and references for safer function interfaces.
Use std::vector instead of raw arrays when possible.
Favor smart pointers over raw pointers for ownership.
Write small, focused functions and keep code readable.

Example

cpp

#include <iostream>
#include <vector>
#include <string>

int main() {
    std::vector<std::string> names = {"Ada", "Grace", "Linus"};
    for (const auto& name : names) {
        std::cout << name << std::endl;
    }

    return 0;
}

Summary

C++ is an excellent choice when you need control, performance, and scalability. Mastering its foundations — types, control flow, functions, classes, and the STL — will prepare you for systems programming, game development, and high-performance applications.

C++