C++ Introduction

What Is C++?

C++ is a general-purpose compiled programming language. It extends C with object-oriented features such as classes, inheritance, and polymorphism, while keeping low-level control for performance-critical software.

Pipeline:
  source (.cpp) → compile → link → executable

I/O:      #include <iostream>, std::cout / std::cin
Entry:    int main()
Build:    g++ file.cpp -std=c++17 -Wall -o out

C++ powers games, browsers, operating systems, and embedded systems. This page is the gateway to the C++ tutorials—patterns, strings, and interview programs have their own pages.

Why Use C++?

Bjarne Stroustrup created “C with Classes” at Bell Labs so large projects could stay as efficient as C. The name C++ (C incremented) appeared in 1983.

Key milestones

How a C++ Program Runs

Unlike interpreted languages, C++ is built before it runs. Keep this pipeline in mind.

Cheat sheet — building blocks

What Does a C++ Program Look Like?

A minimal console program prints a line and exits with status 0:

#include <iostream>

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

Prefer std:: prefixes in shared code. In tiny learning snippets, using namespace std; is acceptable but avoid it in headers.

C++ vs C

If you know C, map the ideas like this:

Same idea, two styles

Print a greeting:

#include <stdio.h>

int main(void) {
    printf("Hello, World!\n");
    return 0;
}

#include <iostream>

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

When to choose which

Compile and Run Your First Program

Save the hello program as hello.cpp, then build it with g++. Compile-time checks catch many type errors before the program runs.

g++ hello.cpp -std=c++17 -Wall -o hello
./hello          # Linux / macOS
hello.exe        # Windows

Hello, World!

How It Works

1. Compile. g++ reads hello.cpp, applies the C++17 standard, and writes an executable named hello.

2. Warnings. -Wall turns on useful warnings—fix them while you learn.

3. Run. Starting the executable calls main, which prints via std::cout.

Use g++ (not only gcc) for .cpp files so the C++ runtime links correctly. Next, practice logic with C++ interview programs.

Where Is C++ Used?

Common workloads where performance and control matter:

Key Takeaways