Install C++ and Compile Your First Program

C++ is a compiled language. Before writing code, you need a compiler that turns source files into machine code, a linker that stitches object files together, and a standard library. The good news: every major platform ships a one-line install path.

Pick a compiler

The two free, production-grade C++ compilers are GCC (g++) and Clang (clang++). Both implement modern C++ standards. Pick whichever your platform installs first. MSVC on Windows is also fine if you prefer Visual Studio.

Install on macOS

Install Xcode Command Line Tools. This gives you clang++ and the system standard library.

xcode-select --install
clang++ --version

If you want GCC too, install it via Homebrew with brew install gcc. The binary will be named g++-14 or similar to avoid colliding with Apple’s g++ alias.

Install on Linux

Use your distribution’s package manager.

# Debian/Ubuntu
sudo apt update && sudo apt install build-essential
g++ --version

# Fedora
sudo dnf install gcc-c++ make

build-essential pulls in g++, make, and the standard library headers in one shot.

Install on Windows

The simplest path is MSYS2, which gives you a real GCC. Download the installer from msys2.org, then run:

pacman -S mingw-w64-ucrt-x86_64-gcc

Add C:\msys64\ucrt64\bin to your PATH and confirm with g++ --version from a new terminal. If you prefer MSVC, install Visual Studio with the Desktop development with C++ workload.

Your first program

Create a file named hello.cpp.

#include <iostream>

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

Compile it. Always pass a standard flag and turn on warnings; the defaults are too permissive.

g++ -std=c++20 -Wall -Wextra -O2 hello.cpp -o hello
./hello

Breakdown: -std=c++20 selects the language version, -Wall -Wextra enables most useful warnings, -O2 requests optimization, and -o hello names the output binary. On Windows the binary is hello.exe.

Multi-file projects

Real projects span many files. Split declarations into headers and definitions into .cpp files. Create greet.h:

#pragma once
#include <string>

std::string greet(const std::string& name);

Create greet.cpp:

#include "greet.h"

std::string greet(const std::string& name) {
    return "Hello, " + name + "!";
}

Update hello.cpp:

#include <iostream>
#include "greet.h"

int main() {
    std::cout << greet("world") << "\n";
}

Compile both translation units together. The compiler produces object files and the linker merges them.

g++ -std=c++20 -Wall -Wextra hello.cpp greet.cpp -o hello

#pragma once ensures the header is included only once per translation unit, replacing the older include-guard pattern.

A minimal Makefile

Typing the full command each rebuild gets tedious. A small Makefile saves keystrokes:

CXX = g++
CXXFLAGS = -std=c++20 -Wall -Wextra -O2

hello: hello.o greet.o
	$(CXX) $(CXXFLAGS) -o $@ $^

%.o: %.cpp
	$(CXX) $(CXXFLAGS) -c $< -o $@

clean:
	rm -f *.o hello

Run make to build and make clean to wipe artifacts. For larger projects, CMake is the standard build system; learn it once your project has more than a handful of files.

Common pitfalls

• Forgetting -std=c++20 (or c++17) leaves you on an old standard. Modern features will not compile.
• Skipping -Wall -Wextra hides bugs the compiler can detect for free.
• Mixing GCC and Clang standard libraries on macOS can cause link errors. Stick to one toolchain per project.
• On Windows, g++ not being on PATH is the most common confusing error. Open a fresh terminal after editing PATH.

What to learn next

You now have a working compiler. The next steps are the language fundamentals: read Variables and Fundamental Types for how C++ models data, and Control Flow for branching and loops. Once those click, move on to Functions and References.

Wrap up

A C++ toolchain is one package install away on every platform. Always compile with a recent standard, warnings on, and use a build system once you have more than two files. Everything else in C++ builds on this loop: edit, compile, run, repeat.