Tutorial 0: Hello World

COMP6771 Advanced C++ Programming

Today's plan

1. Set up your environment
2. Write and compile your first program
3. Build with CMake
4. A taste of modern C++

Environment

You will need:

• Compiler: GCC 12+ or Clang 15+ (C++20 support)
• Build system: CMake 3.20+
• Editor: Your choice

On CSE machines, these are already available.

g++ --version

Hello World

#include <iostream>
#include <string>

auto main() -> int {
    auto const name = std::string{"COMP6771"};
    std::cout << "Hello, " << name << "!\n";
    return 0;
}

Course style conventions

• auto main() -> int -- trailing return type
• auto const for local variables where possible
• std::string{"..."} -- brace initialisation
• \n over std::endl -- avoids unnecessary flush

Compiling

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

Building with CMake

cmake_minimum_required(VERSION 3.20)
project(hello)

set(CMAKE_CXX_STANDARD 20)
set(CMAKE_CXX_STANDARD_REQUIRED ON)

add_executable(hello hello.cpp)

cmake -B build
cmake --build build
./build/hello

A taste of modern C++

auto const numbers = std::vector{3, 1, 4, 1, 5, 9, 2, 6};

auto evens_doubled = numbers
    | std::views::filter([](int n) { return n % 2 == 0; })
    | std::views::transform([](int n) { return n * 2; });

for (auto const val : evens_doubled) {
    std::cout << val << " ";
}
// Output: 8 4 12

Don't worry if this looks unfamiliar -- it will be second nature by the end.

What's next

• Value semantics and the type system
• STL containers and iterators
• Move semantics and smart pointers
• Templates and generic programming
• Custom iterators and ranges

See you in Tutorial 1!