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using OOP to implement matrix class that provide the basic matrix operations

Mar 27, 2013 at 2:32am
Amima 2 (10)
i want to know how i can solve this question? do i need to create a class or write the program codes, i dont understand it
Mar 27, 2013 at 8:37am
ajh32 (659)
What is the complete question you have been assigned?
Mar 29, 2013 at 2:56pm
Amima 2 (10)
the question is using oop implement a matrix class that provides the basic matrix operations (addition, subtraction, multiplication, Inverse, Transportation).
Mar 29, 2013 at 3:32pm
maeriden (872)
do i need to create a class or write the program codes

To create a class you write the program's code.

Anyway, using oop means that you have to create a class. That class should contain a matrix (meaning an array of arrays) of elements on which you will perform the calculations needed by matrix operations.
Mar 30, 2013 at 5:56am
Amima 2 (10)
ok, thank you maeriden. I will try and it to you and see if there is any mistake, tanks
Apr 1, 2013 at 5:57am
Amima 2 (10)
this is the solution, pls someone should help me with the correction, the question is using oop implement a matrix class that provides the basic matrix operations (addition, subtraction, multiplication, Inverse, Transportation).

#include <iostream>
using namespace std;
int main;

class matrix
{
int **p, m, n;
public:
matrix(int row = 2, int col = 2)
{
m = row;
n = col;
p = new(int *); m;
for (int i = 0; i < m; i++)
p[i] = new int[n];
}
~matrix()
{
for (int i = 0; i < m; i++)
delete p[i];
delete p;
}
void accept()
{
cout<<"Enter matrix elements:";
for(int i = 0; i < m; i++)
{
for(int j = 0; j < n; j++)
{
cin >> p[i][j];
}
}
}
void display()
{
cout <<"The matrix is:";
for(int i = 0; i < m; i++)
{
cout <<endl;
for(int j = 0; j < n; j++)
{
cout << p[i][j] <<" ";
}
}
}
matrix operator +(matrix m2)
{
matrix T(m, n);
for(int i = 0; i < m; i++)
{
for(int j = 0; j < n; j++)
{
T.p[i][j] = p[i][j] + m2.p[i][j];
}
}
return T;
}
friend matrix operator * (matrix, matrix);
};
matrix operator * (matrix a , matrix b)
{
if(a.n == b.m)
{
matrix T(a.m, b.n);
for(int i = 0; i < a.m; i++)
{
for(int k = 0; k < b.n; k++)
{
T.p[i][k] = 0;
for(int j = 0; j < a.n; j++)
{
T.p[i][k]+= a.p[i][j] * b.p[j][k];
}
}
}
return T;
}
}
Apr 1, 2013 at 7:00am
Smac89 (1727)
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#include <iostream>
using namespace std;

class matrix
{ 
   int **p, m, n; 
public: 
   matrix(int row, int col) 
   { 
      m = row; 
      n = col; 
      p = new int*[m]; 
      for (int i = 0; i < m; i++) 
	 p[i] = new int[n]; 
   }
   ~matrix() 
   { 
      for (int i = 0; i < m; i++) 
	 delete p[i]; 
      delete p; 
   } 
   void accept() 
   { 
      cout<<"Enter matrix elements:"; 
      for(int i = 0; i < m; i++) 
      { 
	 for(int j = 0; j < n; j++) 
	 { 
	    cin >> p[i][j]; 
	 } 
      } 
   } 
   void display() 
   { 
      cout <<"The matrix is:";
      for(int i = 0; i < m; i++) 
      { 
	 cout <<endl; 
	 for(int j = 0; j < n; j++) 
	 { 
	    cout << p[i][j] <<" "; 
	 } 
      } 
   }
   matrix operator +(matrix m2)
   {
      matrix T(m, n);
      for(int i = 0; i < m; i++)
      {
	 for(int j = 0; j < n; j++)
	 {
	    T.p[i][j] = p[i][j] + m2.p[i][j]; 
	 } 
      }
      return T;
   }
   
   matrix operator= (matrix eq)
   {
      m = eq.m;
      n = eq.n;
      p = eq.p;
      
      return *this;
   }
   
   friend matrix operator * (matrix, matrix);
};

matrix operator* (matrix a , matrix b)
{
   matrix B(1,1);
   if(a.n == b.m)
   {
      matrix T(a.m, b.n);
      for(int i = 0; i < a.m; i++)
      {
	 for(int k = 0; k < b.n; k++)
	 {
	    T.p[i][k] = 0;
	    for(int j = 0; j < a.n; j++)
	    {
	       T.p[i][k]+= a.p[i][j] * b.p[j][k];
	    }
	 }
      }
      B = T;
   }
   return B;
}

int main()
{
   matrix rf(3,3);
}
Edit & run on cpp.sh
Apr 2, 2013 at 3:03am
Amima 2 (10)
Thank you smac89, it compile successfully but when i run the program it prints process exited with return value 0, pls what can i do?
Apr 2, 2013 at 7:39am
Smac89 (1727)
You have to add more things for it to do:

Here is a revision of the previous, still has some bugs. I have to use friend operators instead of matrix operators to avoid overwritting valueable data. This can be easily. I will check back here tomorrrow

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#include <iostream>
using namespace std;

class matrix
{ 
   int **p, m, n; 
public: 
   matrix(int row, int col) 
   { 
      m = row; 
      n = col; 
      p = new int*[m]; 
      for (int i = 0; i < m; ++i)
      {
	 p[i] = new int[n];
	 for (int j = 0; j < n; ++j)
	    p[i][j] = 0;
      }
   }
   
//    ~matrix() 
//    { 
//       delete [] p;
//    }
   
   void accept() 
   { 
      cout<<"Enter matrix elements: "; 
      for(int i = 0; i < m; i++) 
      { 
	 for(int j = 0; j < n; j++) 
	 { 
	    cin >> p[i][j]; 
	 } 
      } 
   }
   
   void display() 
   { 
      cout <<"The matrix is:\n";
      for(int i = 0; i < m; i++) 
      { 
	 for(int j = 0; j < n; j++) 
	 { 
	    cout << p[i][j] <<" "; 
	 }
	 cout <<endl;
      } 
   }
   
   matrix& operator+ (matrix& lhs, const matrix& m1)
   {
      return (*this += m1);
   }
   
   matrix& operator* (const matrix& m1)
   {
      return (*this *= m1);
   }
   
   matrix& operator+= (const matrix& rhs)
   {
      for(int i = 0; i < m; i++)
      {
	 for(int j = 0; j < n; j++)
	 {
	    p[i][j] += rhs.p[i][j]; 
	 } 
      }      
      return *this;
   }
   
   matrix& operator*= (const matrix& T)
   {
      if(n == T.m)
      {
	 for(int i = 0; i < T.m; ++i)
	 {
	    for(int k = 0; k < n; ++k)
	    {
		 p[i][k] *= T.p[k][i];
	    }
	 }
      }
      
      return *this;
   }
   
   matrix& operator= (const matrix& T)
   {
      p = T.p;
      n = T.n;
      m = T.m;
      
      return *this;
   }
   
};


int main()
{
   matrix rf(3,3), ff(3,3);
   rf.accept();
   cout << "\nrf\n";
   rf.display();
   
   ff.accept();
   cout << "\nff\n";
   ff.display();
   
   cout << "\nff = ff + rf\n";
   ff = ff + rf;
   ff.display();
   
   cout << "\nff = (rf * ff)\n";
   ff = (rf * ff);
   ff.display();
   
   cout << "\nrf += ff\n";
   rf += ff;
   rf.display();
}
Edit & run on cpp.sh
Last edited on Apr 2, 2013 at 7:46am
Apr 2, 2013 at 8:19am
ajh32 (659)
So you sent me a private msg last Friday asking me to do this assignment for you. I foolishly wrote the code on Saturday, but as you haven't replied to any of my messages, I haven't handed the code over. Good luck...
Last edited on Apr 2, 2013 at 8:19am
Apr 2, 2013 at 3:25pm
eklavya sharma 2 (170)
You could use a pseudomatrix
http://www.cplusplus.com/doc/tutorial/arrays/
See the "pseudo-multidimensional array" part.

I have made my own matrix class using a pseudo-multidimensional array
Last edited on Apr 2, 2013 at 3:28pm
Apr 2, 2013 at 3:37pm
ajh32 (659)
You could use a pseudomatrix
http://www.cplusplus.com/doc/tutorial/arrays/
See the "pseudo-multidimensional array" part.

I have made my own matrix class using a pseudo-multidimensional array


Yes, that's what I did with my solution, except I used a vector.
Apr 5, 2013 at 6:02am
Amima 2 (10)
please im so sorry ajh32, i didnt receive any of your message, thank you @ eklavya sharma 2, scam89, and ajh32, i really appreciate your contributions, i will do it know, thanks once again
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