Operator Overloading problem

Ugh alright thanks, guess Ill be hitting up Google all night..

Originally Posted by omGeeK

Why is the compiler giving me problems on the swap saying its invalid argument?

Uh, because you are not using your temp variable. It should have been:

Code:

Matrix temp(mMatrix);
swap(temp);

You cannot swap with mMatrix as mMatrix is a const reference, but the parameter of swap is a non-const reference.

Originally Posted by grumpy

Because your swap is a non-static member function, and can only be used in the form "some_object.swap(some_other_object)" rather than as a naked function call.

No, that is not the problem because in the context of a non-static member function that is a valid non-static member function call equivalent to this->swap(mMatrix);

Originally Posted by laserlight

No, that is not the problem because in the context of a non-static member function that is a valid non-static member function call equivalent to this->swap(mMatrix);

Indeed. Place that within the 3% mentioned in my signature

That test for self-assignment is bad practice.

Requiring the test for it to work is bad practice; having the test as a "short circuit" path to prevent a needless copy isn't bad practice just completely unnecessary.

Soma

Alright I'm back with some heap errors. I have debugged the crap out of it and I don't understand the problem. At random points when my destructor gets called I will get heap errors even though I know there is a valid address their that was allocated by new[]..

Well heres my class code

Code:

#include "Matrix.h"
//default constructor
Matrix::Matrix()
{
	_name = "";
	_row = 0;
	_col = 0;
	_mat = NULL;
}
//copy constructor call
Matrix::Matrix(const Matrix &m)
{
	int i,j;
	_row = m._row;
	_col = m._col;
	_name = m._name;
	errorInput = m.errorInput;
	_mat = new double *[_row];
	for(i=0;i<_row;i++)
	{
		_mat[i] = new double [_col];
		for(j=0;j<_col;j++)
		{
			_mat[i][j] = m._mat[i][j];
		}
	}
}
//destructor
Matrix::~Matrix()
{
	if(_mat)
	{
		for(int i = 0; i < _row; i++)
		{
			cout << _mat[i] << "\n";
			delete[] _mat[i];
		}
		delete[] _mat;
		_mat = NULL;
	}
}
//swap for the copy
void Matrix::swap(Matrix& m) 
{
	using std::swap;       
	swap(_name, m._name);     
	swap(_row, m._row); 
	swap(_col, m._col);
	swap(errorInput, m.errorInput);
	swap(_mat,m._mat);
}
//returns the name of a matrix
string Matrix::getName(void)
{
	return _name;
}
//returns the number of rows
int Matrix::getRow(void)
{
	return _row;
}
//returns the number of columns
int Matrix::getCol(void)
{
	return _col;
}
//clear the matrix
void Matrix::clear(void) 
{     
	Matrix temp;     
	swap(temp); 
} 

//this sets the name of the string passed to matrixs name
void Matrix::setName(string name)
{
	_name.clear();
	_name = name;
}
//this displays the matrix to cout
void Matrix::dispMatrix(void)
{
	int i,j;
	cout << _name << " =" << endl;
	for(i=0;i<_row;i++)
	{
		for(j=0;j<_col;j++)
		{
			cout << "\t" << _mat[i][j];
		}
		cout << endl;
	}
	cout << endl;
}
//transpose a matrix
Matrix Matrix::transpose(void)
{
	Matrix temp(*this);
	Matrix temp1;
	temp1._row = temp._col;
	temp1._col = temp._row;
	temp1._mat = new double *[temp1._row];
	for(int i = 0; i < temp1._row; i++)
	{
		temp1._mat[i] = new double [temp1._col];
		for(int j = 0; j < temp1._col; j++)
		{
			temp1._mat[i][j] = temp._mat[j][i];
		}
	}
	return temp1;
}
//sets the data of a matrix given a matrix operator overloading
Matrix & Matrix::operator = (const Matrix& mMatrix)
{
	if (this != &mMatrix) // protect against invalid self-assignment
	{
		Matrix temp(mMatrix);
		swap(temp);
	}
	// by convention, always return *this
	return *this;
}
std::istream& operator>>(std::istream &is, Matrix & mMatrix)
{
	string tempString,tempString1;
	istringstream tempNumString;
	deque<string> sList;
	int row = 0;
	int col = 0;
	int loopGo = 1;
	int foundEnd = 0;
	int lastCol = 0;
	double tempDBL;
	std::ios_base::fmtflags temp=is.flags();
	cin >> tempString;
	while(loopGo)
	{
		if(cin.peek() == '\n')
		{
			loopGo = 0;
		}
		if(tempString.find('[') != string::npos)
		{
			if(tempString.size() > 1)
			{
				tempString = tempString.substr(tempString.find('[') + 1,tempString.size());
				col ++;
			}
		}
		else if(tempString.find(']') != string::npos)
		{
			foundEnd = 1;
			if(tempString.size() > 1)
			{
				tempString = tempString.substr(0,tempString.find(']'));
				col ++;
			}
			row++;
		}
		else if(tempString.find(';') != string::npos)
		{
			if(tempString.size() > 1)
			{
				if(tempString.front() == ';')
				{
					tempString = tempString.substr(1, tempString.size());
				}
				else if(tempString.back() == ';')
				{
					tempString = tempString.substr(0, tempString.size()-1);
					col++;
				}
				else
				{
					tempString1 = tempString.substr(0,tempString.find(';') - 1);
					col++;
					sList.push_front(tempString1);
					tempString1 = tempString.substr(tempString.find(';') + 1,tempString.size());
				}
			}
			if(lastCol == 0)
			{
				lastCol = col; 
				row++;
				col = 0;
			}
			else if(lastCol == col)
			{
				row ++;
				col = 0;
			}
			else
			{
				mMatrix.errorInput = 2;
				return is;
			}
		}
		else
		{
			col ++;
		}
		if(tempString != "[" && tempString != ";" && tempString != "]")
		{
			for(string::iterator sIT = tempString.begin(); sIT != tempString.end(); ++sIT)
			{
				if(*sIT < 48 || *sIT > 57)
				{
					mMatrix.errorInput = 3;
					return is;
				}
			}
			sList.push_back(tempString);
		}
		if(loopGo)
			cin >> tempString;
	}
	if(foundEnd != 1)
	{
		mMatrix.errorInput = 4;
		return is;
	}
	mMatrix.errorInput = 1;
	mMatrix._row = row;
	mMatrix._col = col;
	mMatrix._mat = new double *[row-1];
	for(int i=0;i<row;i++)
	{
		mMatrix._mat[i] = new double [col-1];
		for(int j=0;j<col;j++)
		{
			tempNumString.str(sList.front());
			tempNumString >> tempDBL;
			sList.pop_front();
			tempNumString.clear();
			mMatrix._mat[i][j] = tempDBL;
		}
	}

	is.flags(temp);
	return is;
}

Code:

vector<Matrix>::iterator mIT = mList.begin();
							for(int l = 0; l < pos ;l ++)
							{
								++mIT;
							}
							mList.erase(mIT);
							temp.clear();
							cin >> temp;
							temp.setName(cmd);
							addMatrix(mList,temp);

I get an error on the temp.clear() call when it uses the destructor of the temp matrix.