How to add two matrices in c++ -

i write class , have problem adding matrices. know have overload operator +, don't know how exactly. ideas ?

 class cmatrix   {     private:             int rows;             int columns;             float* pdata;      public:             cmatrix(void);             cmatrix(int rows, int columns);                             void setelement(int row, int column, float element);             float getelement(int row, int column);    ...};     istream& operator>>(istream& in, cmatrix& matrix)      { in >> matrix.rows; in >> matrix.columns;  for(int = 0; < matrix.rows; i++)     for(int j = 0; j < matrix.columns; j++)         in >> *(matrix.pdata + * matrix.columns + j);  return in;     }         cmatrix::cmatrix(int rows, int columns)     {     rows = rows;     columns = columns;     pdata = new float[rows * columns];      float* pend = &pdata[rows * columns];      for(float* p = pdata; p < pend; p++)             *p = 0.0;       }       void cmatrix::setelement(int row, int column, float element)     {       *(pdata+  row * columns + column) = element;       }      float cmatrix::getelement(int row, int column)      {        return *(pdata + row * columns + column);       } 

overloaded operators '<<' ,'>>' , have problem operator +.

unfortunatelly have less 10 reputation...so if write:

 cmatrix operator+(const cmatrix &lhs, const cmatrix &rhs)     {  cmatrix result (rows,columns); for(int i=0; <rows ; i++) for( int j=0; j<columns; j++)  result.setelement(i,j)  = lhs.getelement(i,j) + rhs.getelement(i,j);    return result;        }    int main()    { const int n = 10, m = 5;  cmatrix m1(n, m);      cmatrix m2(n, m);  for(int = 0; < n; i++)     for(int j = 0; j < m; j++)         m1.setelement(i, j, (float)(i * m + j));      for(int = 0; < n; i++)         for(int j = 0; j < m; j++)         m2.setelement(i, j, (float)(i * m + j));     cout<<m1+m2;  // doesn't work    help, did @ last... 

unless need access private members of cmatrix perform computation, recommend create non-member function following prototype:

cmatrix operator+(const cmatrix &lhs, const cmatrix &rhs) {   // work    // may need throw exceptions based on incompatibilities between   // matrix configurations (i.e., dimensions) } 

you should add copy constructor, destructor, , assignment operators (maybe move constructor , move assignment well) or consider disabling these operations. if not, run serious issues compiler supplied defaults if code employs them.

you need add destructor, because leak memory if not.