2021 Advent of Code C++ Templates

This Repository contains C++ templates for 2021 Advent of Code. The templates are meant to help beginners to C++ with writing solutions by providing a framework which reads in the data.

The template reads in from standard input (std::cin), stores the input in global variables before calling solve(). This solve() function is where users should write their solution to the Advent of Code problem.

Building the Solution

Basic Compilation on Linux

The most basic way to compile the code.

This method is very basic and so any runtime code errors will not have nice logs which tell you where the error is. For these helpful tools it is recommended to compile using CMake.

Step by step guide:

1. Navigate to the directory which contains the solution source code.
2. Run g++ <input_file> -o solution.exe
   This will compile to an executable solution.exe

user@computer:~/AoC2021Templates$ cd Day1
user@computer:~/AoC2021Templates/Day1$ g++ solution.cpp -o solution.exe

Now we have solution.exe, we can run it and pipe in the input file.

user@computer:~/AoC2021Templates/Day1$ ./solution.exe < test.txt
Depths: [199, 200, 208, 210, 200, 207, 240, 269, 260, 263]
Solution: 0

Using CMake

To Compile using CMake, navigate to the build directory, configure cmake and then run cmake build. This will build all the days' solutions to an executable inside the Day* folder.

user@computer:~/AoC2021Templates$ cd build
user@computer:~/AoC2021Templates/build$ cmake ..
user@computer:~/AoC2021Templates/build$ cmake --build . --target all

user@computer:~/AoC2021Templates/build$ cd ../Day1
user@computer:~/AoC2021Templates/Day1$ ./solution.exe < test.txt
Depths: [199, 200, 208, 210, 200, 207, 240, 269, 260, 263]
Solution: 0

To compile in Debug mode:

user@computer:~/AoC2021Templates$ cd build
user@computer:~/AoC2021Templates/build$ cmake .. -DCMAKE_BUILD_TYPE=Debug
user@computer:~/AoC2021Templates/build$ cmake --build . --target all

The CMake files for this project have sanitizer and static analyzer options. The most useful sanitizer will probably be the address sanitizer which will print more information about segmentation faults, including the line on which they occur.

user@computer:~/AoC2021Templates$ cd build
user@computer:~/AoC2021Templates/build$ cmake .. -DCMAKE_BUILD_TYPE=Debug -DENABLE_SANITISER_ADDRESS=TRUE
user@computer:~/AoC2021Templates/build$ cmake --build . --target all

Instead of building all targets, it's possible to specify specific source files to compile. The target names are all formatted as Day#-<source_file>.

For example, to build only Day1/solution.cpp, we can run:

user@computer:~/AoC2021Templates$ cd build
user@computer:~/AoC2021Templates/build$ cmake .. -DCMAKE_BUILD_TYPE=Debug -DENABLE_SANITISER_ADDRESS=TRUE
user@computer:~/AoC2021Templates/build$ cmake --build . --target Day1-solution

Print Helpers

print_helpers.hpp is a header file with some overloads for std::ostream operator<<. This is to allow for easy printing of common datatypes such as std::vector. Once this print_helpers.hpp is included, we can simply pipe common standard structures to console using:

#include "print_helpers.hpp"
#include <iostream>

int main()
{
    std::vector<int> vector = std::vector<int>(10);
    std::cout << "Print a Vector: " << vector << std::endl;
}

print_helpers.hpp allows printing std::vector, std::array, std::pair, std::map, std::unordered_map, std::set, std::unordered_set.