C++ Compilation on Linux

Intro

Compiling C++ in Linux using the G++ compiler in the terminal. Most Linux distributions come with g++ (GNU C++ compiler).

g++ command

g++ is the GNU C++ compiler invocation command used for preprocessing, compilation, assembly, and linking of source code to generate an executable file.

Quick Commands

g++ main.cpp -o program
./program

g++ main.cpp my_computations.cpp -o program

Reference

• Video tutorial: https://www.youtube.com/watch?v=FlZp03hMfiw

---

Installation

Check g++ compiler version

g++ --version

Output

g++ (Ubuntu 13.3.0-6ubuntu2~24.04.1) 13.3.0
Copyright (C) 2023 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

Install if needed

sudo apt install g++

---

Compile a Single C++ File

Create a main.cpp file

main.cpp

#include <iostream>
 
int main()
{
    std::cout << "Compile me if you can" << std::endl;
    return 0;
}

Compile the program

g++ main.cpp -o test_program

Run the program

./test_program

Output

Compile me if you can

---

Useful Compiler Flags

• -Wall → enable common compiler warnings
• -O2 → optimization level 2
• -std=c++17 / -std=c++20 / -std=c++23 → specify language standard
• -g → include debug information for gdb

Example usage:

g++ -std=c++20 -Wall -O2 main.cpp -o program

---

Compile Multiple Files

Project Structure

project/
├── main.cpp
├── my_computations.cpp
└── my_computations.hpp

---

main.cpp

main.cpp

#include <iostream>
#include "my_computations.hpp"
 
int main()
{
    std::cout << "Double of 3 is " << double_number(3) << std::endl;
    std::cout << "10 C = " << celcius_to_farenheit(10) << std::endl;
 
    double area = compute_rectangle_area(3.4, 5.6);
    std::cout << "Area of rectangle is " << area << std::endl;
 
    return 0;
}

Header File

my_computations.hpp

#ifndef MY_COMPUTATIONS_HPP
#define MY_COMPUTATIONS_HPP
 
int double_number(int number);
double celcius_to_farenheit(double celcius_degrees);
double compute_rectangle_area(double length, double width);
 
#endif

Implementation File

my_computations.cpp

#include "my_computations.hpp"
 
int double_number(int number) {
    return 2 * number;
}
 
double celcius_to_farenheit(double celcius_degrees) {
    return (celcius_degrees * 9.0 / 5.0) + 32.0;
}
 
double compute_rectangle_area(double length, double width) {
    return length * width;
}

---

Compile all files

g++ main.cpp my_computations.cpp -o my_program

Run the program

./my_program

Output

Double of 3 is 6
10 C = 50
Area of rectangle is 19.04

---

Makefile (Automation)

Makefile

CXX = g++
CXXFLAGS = -std=c++20 -Wall -O2
 
program: main.o my_computations.o
    $(CXX) $(CXXFLAGS) main.o my_computations.o -o program
 
main.o: main.cpp
    $(CXX) $(CXXFLAGS) -c main.cpp
 
my_computations.o: my_computations.cpp
    $(CXX) $(CXXFLAGS) -c my_computations.cpp
 
clean:
    rm -f *.o program

Run:

make

Run program:

./program

Clean build files:

make clean