c++ - operator = overload in template class -

im working on matrix template class, , should write "=" operator overload. im trying delete matrix appears in left side of '=', , return new 1 equals matrix appears in right side of '='.

because can't delete "this" distructor, delete "manually" in function. should make new matrix, therefor make new 1 ("temp") , return it. prblem "temp" return, doesn't set in matrix appears in left side of '='.

the code:

matrix<int> m (3, 4);     matrix<int> m2(2, 5);     m2 = m; 

this main part.

the function:

template<class t> matrix<t> & matrix<t>::operator=(matrix<t>& mat) {     if (this==&mat)     {         return *this;     }      (int = 0; < this->rows; i++)     {         delete[] this->mat[i];     }      delete[] this->mat;      matrix<t> * temp = new matrix<t>(mat.rows, mat.cols);      (int = 0; < temp->rows; i++)         (int j = 0; j < temp->cols; j++)         {             temp->mat[i][j] = mat.mat[i][j];         }      return *temp; }   template<class t> matrix<t>::matrix(int row, int col) {     rows = row;     cols = col;     mat = new t*[rows];     (int = 0; < rows; i++)     {         mat[i] = new t[cols];     }     rester(*this); } 

thx!!

use std::vector storage (instead of manal new , delete), , accept copy assignment operator generated compiler. it's easy.

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if absolutely want implement copy assignment yourself, learning, express copy assignment in terms of copy construction.

to that, first define noexcept swap operation:

// in class definition: friend void swap( matrix& a, matrix& b )     noexcept {     using std::swap;     // swap data members here } 

then copy assignment operator can expressed simply

// in class definition auto operator=( matrix other )     -> matrix& {     swap( *this, other );     return *this; } 

it's popular, idiom, because it's simple yet exception safe.

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instead of returning reference, adds verbosity , possible marginal inefficiency no gain, might want use void return type. however, historical reasons, containers in standard library require copy assignment operator return reference self.