《Essential C++》系列笔记之第四章(基于对象的编程风格)之第八节(实现一个copy assignment operator)

代码实践

• main.cpp

  #include 
  #include "Matrix.h"
  using namespace std;
  
  int main()
  {
  	Matrix m0(3, 3);  //初始化使用拷贝构造
  	//Matrix m1(m0);
  	Matrix m1(2, 2);
  	m1 = m0;         //赋值使用重载=
  
  	system("pause");
  	return 0;
  }
  

• Matrix.h

  #pragma once
  #include 
  using namespace std;
  class Matrix
  {
  public:
  	Matrix(int row, int col)
  		:_row(row), _col(col)
  	{
  		_pmat = new double[col * row];
  	}
  	~Matrix();
  	Matrix(const Matrix& rhs);
  	void operator=(Matrix&);
  private:
  	int _row, _col;
  	double* _pmat;
  };
  

• Matrix.cpp

  #include "Matrix.h"
  
  Matrix::~Matrix()
  {
  	delete[] _pmat;
  }
  
  Matrix::Matrix(const Matrix& rhs)
  	:_row(rhs._row), _col(rhs._col)
  {
  	cout << "Matrix::Matrix(const Matrix& rhs)" << endl;
  	this->_pmat = new double[_row * _col];
  	for (int i = 0; i < _row * _col; i++)
  	{
  		this->_pmat[i] = rhs._pmat[i];
  	}
  }
  
  void Matrix::operator=(Matrix&rhs)
  {
  	this->_col = rhs._col;
  	this->_row = rhs._row;
  	cout << "Matrix::operator=(Matrix&rhs)" << endl;
  	this->_pmat = new double[rhs._col * rhs._row];
  	for (int i = 0; i < _row * _col; i++)
  	{
  		this->_pmat[i] = rhs._pmat[i];
  	}
  }
  

今天还是20200325 初始化与赋值是好兄弟!