Thread: How to make MoveConstructor and MoveOperator work?

PHP Code:

I read your interesting article:http://www.cprogramming.com/c++11/rvalue-references-and-move-semantics-in-c++11.htmland tried to follow the contained suggestionsBut after many trials I still do not understand how to properly take advantage of the move semantics in order to not copy the result of the operation and just use the pointer, or std::move, to "exchange" the data pointed to. This will be very usefull to speed-up more complicated functions like f(g(),h(i(l,m),n(),p(q()))
Executing the code below: 


Code:

t3={2,4,6} and t1={1,2,3}

while the objective is to have:

Code:

t3={2,4,6} adnd t1={}

Code:

namespace MTensor {

  typedef std::vector<double> Tensor1DType;

  class Tensor1D {
  private:
    //std::shared_ptr<Tensor1DType> data = std::make_shared<Tensor1DType>();
    Tensor1DType * data = new Tensor1DType;
  public:
    Tensor1D() {
    };
    Tensor1D(const Tensor1D& other) {
      for(int i=0;i<other.data->size();i++) {
        data->push_back(other.data->at(i));
      }
    }

    Tensor1D(Tensor1D&& other) : data(std::move(other.data)) {
      other.data = nullptr;
    }

    ~Tensor1D() {
      delete data;
    };
    int size() {
      return data->size();
    };

    void insert(double value) {
      data->push_back(value);
    }

    void insert(const std::initializer_list<double>&  valuesList) {
      for(auto value : valuesList) {
        data->push_back(value);
      }
    }

    double operator() (int i) {
      if(i>data->size()) {
        std::cout << "index must be within vector dimension" << std::endl;
        exit(1);
      }
      return data->at(i);
    }

    Tensor1D& operator=(Tensor1D&& other)  {
      if (this == &other){
        return *this;
      }
      data = other.data;
      other.data = nullptr;
      return *this;
    }

    void printTensor(Tensor1DType info) {
      for(int i=0;i<info.size();i++) {
        std::cout << info.at(i) << "," << std::endl;
      }
    }
    void printTensor() {
      for(int i=0;i<data->size();i++) {
        std::cout << data->at(i) << "," << std::endl;
      }
    }
  };


} // end of namespace MTensor



MTensor::Tensor1D scalarProduct1D(MTensor::Tensor1D t1, double scalar) {
  MTensor::Tensor1D tensor;
  for(int i=0;i<t1.size();++i) {
    tensor.insert(t1(i) * scalar);
  }
  //return std::move(tensor);
  return tensor;
}


int main() {
  MTensor::Tensor1D t1;
  t1.insert({1,2,3});
  std::cout << "t1:" << std::endl;
  t1.printTensor();
  MTensor::Tensor1D t3(scalarProduct1D(t1,2));
  std::cout << "t3:" << std::endl;
  t3.printTensor();
  std::cout << "t1:" << std::endl;
  t1.printTensor();
  return 0;
}