C++ 函数的未来展望：新特性和最佳实践如何塑造 C++ 的未来？

struct Person {
  std::string name;
  int age;
};

// 传统方式
Person person = { "John", 25 };
std::string name = person.name;
int age = person.age;

// 结构化绑定
auto [name, age] = person;

template<typename T>
requires std::is_integral_v<T>
void print_int(T value) {
  std::cout << value << std::endl;
}

int main() {
  print_int(10);  // 合法，因为 int 是整数类型
  // print_int(std::string("Hello"));  // 非法，因为 std::string 不是整数类型
}

int divide(int a, int b) noexcept {
  return a / b;
}

int main() {
  try {
    divide(10, 0);
  }
  catch (...) {
    std::cerr << "An error occurred." << std::endl;
  }
}

// 编译时优化，因为编译器知道 divide() 不抛出异常

struct Employee {
  std::string name;
  double hours;
  double rate;
};

double calculate_salary(const Employee& employee) {
  auto [name, hours, rate] = employee;
  return hours * rate;
}

int main() {
  Employee john = { "John", 40, 25.0 };
  std::cout << "John's salary: " << calculate_salary(john) << std::endl;
}

template<typename T>
concept Printable = requires(T t) {
  { std::cout << t; } -> std::ostream&;
};

void print_file(std::ifstream& file) {
  for (std::string line; std::getline(file, line);)
    std::cout << line << std::endl;
}

int main() {
  std::ifstream file("myfile.txt");
  print_file(file);
}