static int add(int x, int y) {

return x + y;

}

int inc(int x) {

return x + 1;

}

void register_commands() override {

register_command(add, "add", "Add two numbers");

register_command(&Arithmetic::inc, "inc", "Increment a number");

}

Arithmetic arithmetic;

std::string text;

std::cout << ">>> ";

while (std::getline(std::cin, text)) {

std::cout << arithmetic.eval(text) << std::endl << std::endl;

std::cout << ">>> ";

}

return 0;