Hello all,

Could anyone tell me why I am losing my object? and possibly how I could correct this problem?

I am having alot of trouble with this function. I would like to return an object by reference from a function, but somewhere between my "return" statement and assigning the result the reference to my returned object gets lost. I don't know why but the destructor is fired by the time I get back inside my assignment operator.

I have tried to include the least amount of code needed to show my problem. Please forgive me for its lengthiness.

Some how after the returning from theoperator*and after just entering the assignment (=) operator my returned matrix object is lost. When I go through debugging, the object is still good but is lost before the "if (right.get_length()!=get_length)"statement. I identified this by watching theobject.aptrvalue change from what it was before the return statement. It appears to still be correct when I get to the first line of the assignment operator definition but not after that.

Thanks for any comments.

-fisher

Code:#include "Matrix.h" int main(){ matrix<int> MAT(3),MAT2(3); for (int j=1; j<=3; j++){ for (int i=1; i<=3; i++){ MAT(i,j)=1; } } MAT2=MAT*MAT; //at the moment, this is the troublesome line <--------------------------- return 0; }Code://Matrix.h #ifndef MATRIX_H #define MATRIX_H #include <iostream> #include <cstdarg> //for using variable argument functions template <class T> class matrix { protected: T *aptr; int *size; //adjustable array of size of each matrix dimension int dim; //number of dimensions of matrix int array_length; //total number of elements in matrix // array_length=size[0]*size[1]*...*size[dim-2]*size[dim-1] char type; public: // CONSTRUCTOR PROTOTYPES matrix();//default constructor matrix(int);// two-dimensional square matrix constructor matrix(int, int, ...);//an any dimensional matrix ~matrix(){cout<<"matrix distroyed"<<endl;} //*** --- operators ----*** T &operator()(int, ...);//reference operator: matrix(i,j,...)=matrix[i-1][j-1]... const matrix &operator= (const matrix &);//assignment operator //multiplication const matrix &operator* (matrix &); }; template <class T>//an any dimensional array matrix<T>::matrix(int d, int n, ...){ int i; va_list list; if(d>0){ dim=d; size= new int[dim]; size[0]=n; array_length=n; va_start(list, n); for(i=1;i<d;i++){ size[i]=va_arg(list,int); array_length *= size[i]; } aptr= new T[array_length]; for (i=0;i<array_length;i++) aptr[i]=0; } va_end(list); } template <class T>//reference operator T &matrix<T>::operator()(int row, ...){ int i, prod=0, element=0; va_list list; va_start(list, row); prod=size[0]; element= (va_arg(list,int)-1)+size[1]*(row-1); for(i=2;i<dim;i++){ prod*= size[i-1]; element+= prod*(va_arg(list,int)-1); } va_end(list); return aptr[element]; } template <class T> //assignment operator const matrix<T> &matrix<T>::operator= (const matrix<T> &right){<------object lost between here if(&right != this){ //check for self-assignment <-------------------------------------and here //reallocate memory if different amount of space needed if( array_length!=right.array_length ){ array_length=right.array_length; dim=right.dim; delete [] aptr; delete [] size; size= new int[dim]; for(int i=0; i<dim ; i++) size[i]=right.size[i]; aptr= new T[array_length]; } else{//change size of dimensions if necessary if(dim!=right.dim){ dim=right.dim; delete [] size; size= new int[dim]; } for(int i=0; i<dim ; i++){ if (size[i]!=right.size[i]) size[i]=right.size[i]; } } } for(int i=0; i<array_length; i++) aptr[i]=right.aptr[i]; //copy matrix elements return *this; } template<class T>//assumes 2D matrixes const matrix<T> &matrix<T>::operator* (matrix<T> &right){ T sum; if((*this).size[1]==right.size[0]){ matrix<T> new_m(2,(*this).size[0],right.size[1]); //do dot product of rows and columns // in tensor form Cik=Aij*Bjk (sum over j-index) for(int i=1;i<=(*this).size[0];i++){ for(int k=1;k<=right.size[1];k++){ sum=0; for (int j=1; j<=(*this).size[1]; j++){ sum+=(*this)(i,j)*right(j,k); } new_m(i,k)=sum; } } return new_m;//this might not be passing back correctly <----------------------------------- } } #endif