C++ 깊은 복사(Deep Copy)

깊은 복사(Deep Copy)

• 하위 항목을 모두 복사하는 것

  #include <iostream>
  #include <cassert>
  
  class MyString
  {
    char*    data_ = nullptr;
    int        len_ = 0;
  
  public:
    MyString(const char* source = "")
    {
      assert(source);
  
      len_ = std::strlen(source) + 1;
      data_ = new char[len_];
  
      for (int i = 0; i < len_; ++i)
        data_[i] = source[i];
      data_[len_ - 1] = '\0';
    }
  
    ~MyString()
    {
      delete[] data_;
    }
  
    MyString(const MyString& source)
    {
      std::cout << "Copy constructor\n";
  
      len_ = source.len_;
  
      if (source.data_ != nullptr)
      {
        data_ = new char[len_];
  
        for (int i = 0; i < len_; ++i)
          data_[i] = source.data_[i];
      }
      else
        data_ = nullptr;
    }
  
    char*& getString() { return data_; }
  };
  
  int        main()
  {
    using namespace std;
  
    MyString    hello("Hello");
  
    cout << (int*)hello.getString() << endl;
    cout << hello.getString() << endl;
  
    {
      MyString    copy = hello;
  
      cout << (int*)copy.getString() << endl;
      cout << copy.getString() << endl;
    }
  
    cout << hello.getString() << endl;
  }

  • 얕은 복사에서 발생했던 문제가 발생하지 않는다.