matrix operator overloading
Author
Say I had a simple class such as this:
class matrix
{
public:
matrix(int rows, int cols); //allocate a rows x cols matrix
//etc, etc....
private:
int **theMatrix; //will be allocated dynamically
int rows;
int cols;
};
How do you overload the [] operator to properly do this:
matrix someMatrix(5,5); //make a 5 x 5 matrix
//do whatever......
cout << someMatrix[2][4] << endl;
I know how to do it with a single dimension array, but how do you do this with a two dimension array?
thanks,
skitzo_smurf
Edited by - skitzo_smurf on 7/11/00 4:37:20 PM
Edited by - skitzo_smurf on 7/11/00 5:45:21 PM
Author
could someone please help me. I dont mean to be a pest, but I have to go soon and this is really bothering me. I know when you do this with a single dimension array you just overload the [] operator like this....
class matrix //example does not really represent a matrix now
{
public:
matrix(int Width) : width(Width) { data = new int[width]; }
//other stuff
//just return the address of data[x]
int &operator [](int x) { return data[x]; }
private:
int *data; //pointer to a dynamically allocated array
int width;
};
then you could say
matrix someMatrix(5);
//later on....
cout << someMatrix[3] << endl;
please help, and if im doing something wrong here then please tell me.
thanks,
skitzo_smurf
class matrix //example does not really represent a matrix now
{
public:
matrix(int Width) : width(Width) { data = new int[width]; }
//other stuff
//just return the address of data[x]
int &operator [](int x) { return data[x]; }
private:
int *data; //pointer to a dynamically allocated array
int width;
};
then you could say
matrix someMatrix(5);
//later on....
cout << someMatrix[3] << endl;
please help, and if im doing something wrong here then please tell me.
thanks,
skitzo_smurf
class matrix{public: matrix(int w, int h) : width(w), height(h) { data = new (int*)[ width ]; for (int i=0;i<width;i++) data[ i ] = new int[ height ]; } int* operator [](int x) { return data[ x ]; } private: int **data; int width, height;}; there!
matrix return an int* as the result, and that int* is equvalent to an int[] iself.<br>so saying matrix[ j ], first calls matrix to get the pointer fot data and then it references to element j ([ j ]) in that array which gives you data[ j ]. get it? <br><br><font color="red">—————-</font><br><font color="yellow">- Pouya / FOO!!! </font><br><font color="blue">***CENSORED***</font>
Author
thank you very much for the help pouya! I will try immediately.
btw how do you put code in a window like that on this forum?
skitzo_smurf
btw how do you put code in a window like that on this forum?
skitzo_smurf
I don''t remember if this is legal, but give it a shot:
int matrix::operator[] ( int row, int col )
By the way you might want to have the overloaded [] operator return a reference to the int. That way you could do this:
matrix[x][y] = z;
just a thought =)
-RWarden (roberte@maui.net)
int matrix::operator[] ( int row, int col )
By the way you might want to have the overloaded [] operator return a reference to the int. That way you could do this:
matrix[x][y] = z;
just a thought =)
-RWarden (roberte@maui.net)
quote:Original post by skitzo_smurf
thank you very much for the help pouya! I will try immediately.
btw how do you put code in a window like that on this forum?
skitzo_smurf
put it in [ source ] and [ /source ] tags (don''t put the spaces there btw)
----------------
- Pouya / FOO!!!
***CENSORED***
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