C++中Matrix(矩阵)的基本运算( +、-、=、<<)

利用二维指针开辟空间形成二维数组；

原题为设计一个Matrix类，实现基本的矩阵运算；

初次设计为HL[10][10]数组，存放矩阵元素，后改为二维指针；

主要问题存在于二维指针理解的不透彻，无法理解其开辟空间的方法；

HL = new double *[row];

for(i = 0;i < row;i++)

    HL[i] = new double [list];

其次对于不同类型矩阵相加没有找到合适的处理方式，只能手动控制不使不同类型矩阵相加或相减；
其中 row 为行，list为列，HL为存放矩阵的二维指针；

附上一个new运算符的用法；

https://www.cnblogs.com/2015-16/p/11782595.html

 #include<iostream>

 using namespace std;

 class Matrix

 {

     private:

         int row,list;

         double **HL;

     public:

         Matrix(int r_ = , int l_ = );

         Matrix(int r_ , int l_ , double **newone);

         Matrix(const Matrix & rhs);

         ~Matrix();

         Matrix operator + (const Matrix & rhs);

         Matrix operator - (const Matrix & rhs);

         Matrix operator = (const Matrix & rhs);

         friend ostream & operator << (ostream & os , const Matrix & rhs);

 };

 int i,j;

 Matrix::Matrix(int r_ , int l_):row(r_),list(l_)　　//构造函数

 {

     HL = new double *[row];

     for(i = ;i < row;i++)

         HL[i] = new double [list];

     cout<<"please enter Matrix :"<<endl;

     for(i = ;i < row;i++)

         for(j = ;j < list;j++)

             cin>>HL[i][j];

 } 

 Matrix::Matrix(int r_ , int l_ , double **newone ):row(r_),list(l_)　　//构造函数重载，主要用于加法减法中的return使用

 {

     HL = new double *[row];

     for(i = ;i < row;i++)

         HL[i] = new double [list];

     for(i = ;i < row;i++)

         for(j = ;j < list;j++)

             HL[i][j] = newone[i][j];

 } 

 Matrix::Matrix(const Matrix & rhs)

 {

     if(this != & rhs)

     {

         this->row = rhs.row;

         this->list = rhs.list;

         HL = new double *[row];

         for(i = ;i < row;i++)

             HL[i] = new double [list];

         for(i = ;i < row;i++)

             for(j = ;j < list;j++)

                 this->HL[i][j] = rhs.HL[i][j];

     }

 }

 Matrix::~Matrix()　　　　//　析构函数，删除开辟的空间

 {

     cout<<"~ Matrix : row ="<<row<<" , list = "<<list<<endl<<endl;

     for(i = ;i < row;i++)

         delete [] HL[i];

     delete [] HL;

 }

 Matrix Matrix::operator + (const Matrix & rhs)

 {

     if( (this->row == rhs.row)&&(this->list == rhs.list) )

     {

         double **newone;

         int r_,l_;

         r_ = row;l_ = list;

         newone = new double *[row];

         for(i = ;i < row;i++)

             newone[i] = new double [list];

         for(i = ;i < row;i++)

             for(j = ;j < list;j++)

                 newone[i][j] = HL[i][j] + rhs.HL[i][j];

         return Matrix(r_,l_,newone);

     }

 //    else

 //        cout<<"error ——矩阵类型不符 "<<endl;

 }

 Matrix Matrix::operator - (const Matrix & rhs)

 {

     if( (this->row == rhs.row)&&(this->list == rhs.list) )

     {

         double **newone;

         int r_,l_;

         r_ = row;l_ = list;

         newone = new double *[row];

         for(i = ;i < row;i++)

             newone[i] = new double [list];

         for(i = ;i < row;i++)

             for(j = ;j < list;j++)

                 newone[i][j] = HL[i][j] - rhs.HL[i][j];

         return Matrix(r_,l_,newone);

     }

 //    else

 //        cout<<"error ——矩阵类型不符 "<<endl;

 }

 Matrix Matrix::operator = (const Matrix & rhs)

 {

     if((this->row == rhs.row)&&(this->list == rhs.list))

     {

         for(i = ;i < row;i++)

             for(j = ;j < list;j++)

                 this->HL[i][j] = rhs.HL[i][j];

         return (*this);

     }

 //    else

 //        cout<<"error ——矩阵类型不符 "<<endl;

 }

 ostream & operator << (ostream & os,const Matrix & rhs)

 {

     os<<"Matrix : row ="<<rhs.row<<" , list = "<<rhs.list<<endl;

     for(i = ;i < rhs.row;i++)

     {

         for(j = ;j < rhs.list;j++)

             os<<rhs.HL[i][j]<<" ";

         os<<endl;

     }

     return os;

 }

 int main()

 {

     int m,n,x,y;

     cin>>n>>m>>x>>y;

     Matrix aa(n,m),bb(n,m),cc(n,m),dd(x,y);

     cout<<endl<<aa<<endl<<bb<<endl<<cc<<endl<<dd<<endl;

     cout<<(aa+bb+cc)<<endl<<(cc-bb)<<endl;

     return ;

 }

2019-11-02 15:34:51

巴特西

C++中Matrix(矩阵)的基本运算( +、-、=、<<)

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