C++ assignment operators dynamic arrays
- by user2905445
First off i know the multiplying part is wrong but i have some questions about the code.
1. When i am overloading my operator+ i print out the matrix using cout << *this then right after i return *this and when i do a+b on matix a and matix b it doesnt give me the same thing this is very confusing.
2. When i make matrix c down in my main i cant use my default constructor for some reason because when i go to set it = using my assignment operator overloaded function it gives me an error saying "expression must be a modifiable value. although using my constructor that sets the row and column numbers is the same as my default constructor using (0,0).
3. My assignment operator= function uses a copy constructor to make a new matrix using the values on the right hand side of the equal sign and when i print out c it doesn't give me anything
Any help would be great this is my hw for a algorithm class which i still need to do the algorithm for the multiplying matrices but i need to solve these issues first and im having a lot of trouble please help.
//Programmer: Eric Oudin
//Date: 10/21/2013
//Description: Working with matricies
#include <iostream>
using namespace std;
class matrixType
{
public:
friend ostream& operator<<(ostream&, const matrixType&);
const matrixType& operator*(const matrixType&);
matrixType& operator+(const matrixType&);
matrixType& operator-(const matrixType&);
const matrixType& operator=(const matrixType&);
void fillMatrix();
matrixType();
matrixType(int, int);
matrixType(const matrixType&);
~matrixType();
private:
int **matrix;
int rowSize;
int columnSize;
};
ostream& operator<< (ostream& osObject, const matrixType& matrix)
{
osObject << endl;
for (int i=0;i<matrix.rowSize;i++)
{
for (int j=0;j<matrix.columnSize;j++)
{
osObject << matrix.matrix[i][j] <<", ";
}
osObject << endl;
}
return osObject;
}
const matrixType& matrixType::operator=(const matrixType& matrixRight)
{
matrixType temp(matrixRight);
cout << temp;
return temp;
}
const matrixType& matrixType::operator*(const matrixType& matrixRight)
{
matrixType temp(rowSize*matrixRight.columnSize, columnSize*matrixRight.rowSize);
if(rowSize == matrixRight.columnSize)
{
for (int i=0;i<rowSize;i++)
{
for (int j=0;j<columnSize;j++)
{
temp.matrix[i][j] = matrix[i][j] * matrixRight.matrix[i][j];
}
}
}
else
{
cout << "Cannot multiply matricies that have different size rows from the others columns." << endl;
}
return temp;
}
matrixType& matrixType::operator+(const matrixType& matrixRight)
{
if(rowSize == matrixRight.rowSize && columnSize == matrixRight.columnSize)
{
for (int i=0;i<rowSize;i++)
{
for (int j=0;j<columnSize;j++)
{
matrix[i][j] += matrixRight.matrix[i][j];
}
}
}
else
{
cout << "Cannot add matricies that are different sizes." << endl;
}
cout << *this;
return *this;
}
matrixType& matrixType::operator-(const matrixType& matrixRight)
{
matrixType temp(rowSize, columnSize);
if(rowSize == matrixRight.rowSize && columnSize == matrixRight.columnSize)
{
for (int i=0;i<rowSize;i++)
{
for (int j=0;j<columnSize;j++)
{
matrix[i][j] -= matrixRight.matrix[i][j];
}
}
}
else
{
cout << "Cannot subtract matricies that are different sizes." << endl;
}
return *this;
}
void matrixType::fillMatrix()
{
for (int i=0;i<rowSize;i++)
{
for (int j=0;j<columnSize;j++)
{
cout << "Enter the matix number at (" << i << "," << j << "):";
cin >> matrix[i][j];
}
}
}
matrixType::matrixType()
{
rowSize=0;
columnSize=0;
matrix = new int*[rowSize];
for (int i=0; i < rowSize; i++)
{
matrix[i] = new int[columnSize];
}
}
matrixType::matrixType(int setRows, int setColumns)
{
rowSize=setRows;
columnSize=setColumns;
matrix = new int*[rowSize];
for (int i=0; i < rowSize; i++)
{
matrix[i] = new int[columnSize];
}
}
matrixType::matrixType(const matrixType& otherMatrix)
{
rowSize=otherMatrix.rowSize;
columnSize=otherMatrix.columnSize;
matrix = new int*[rowSize];
for (int i = 0; i < rowSize; i++)
{
for (int j = 0; j < columnSize; j++)
{
matrix[i]=new int[columnSize];
matrix[i][j]=otherMatrix.matrix[i][j];
}
}
}
matrixType::~matrixType()
{
delete [] matrix;
}
int main()
{
matrixType a(2,2);
matrixType b(2,2);
matrixType c(0,0);
cout << "fill matrix a:"<< endl;;
a.fillMatrix();
cout << "fill matrix b:"<< endl;;
b.fillMatrix();
cout << a;
cout << b;
c = a+b;
cout <<"matrix a + matrix b =" << c;
system("PAUSE");
return 0;
}
