matrix operator *(matrix b)
{
 matrix ans(r, b.c);	//Allows us to use rows and columns
 float t;
 int i, j, k;

 for (i = 1; i <= r; i++)
{
     for (j = 1; j <= c; j++)
     {
         t = 0;

         for (k = 1; k <= b.r; k++)
         {
              t = t + (mat[k][j] * b.mat[i][j]);
         }

        ans.mat[i][j] = t;
      
     }
    }
     return ans;
}

for (i = 1; i <= r; i++)

for (j = 1; j <= c; j++)

for (i = 0; i < r; i++)

for (j = 0; j < c; j++)

#include <iostream.h>
#include <stdlib.h>
#include <conio.h>

class matrix
{
	private:
		int r, c;	//r - rows, c - columns
		float mat[11][11];
		int errcode;
	public:
		matrix () : r(0), c(0), errcode(1) {  } //Default undefinded
		matrix (int rows, int coulmns) : r(rows), c(coulmns), errcode(0) {  }  
		//Error codes 
		//0 - No error, 1 - undefinded, 2 - size mismatch, 3 - dervied error
		void input()
		{
			char change;
			int i;
			
			if (r != 0 && c != 0)
			{
				cout << "There are " << r << " rows and " << c << " coulmns\n";
				cout << "Do you wish to change it? ";
				cin >> change;
				if (change == 'Y' || change == 'y')
				{
					cout << "How many rows are there? ";
					cin >> r;
					cout << "How many cols are there? ";
					cin >> c;					
				}

				int q = 1;
				while (q <= r)
				{
					cout << "Enter row " << q << ": ";
					for (i = 1; i <= c; i++)	//If the i is equal to the row then exit the loop
					{	
						cin >> mat[q][i]; 
					}	//End for
					q++;
				}	//End while
			} //End if
			else
			{
				cout << "A matrix cannot equal 0\n";
			}	//End else
		}	//End input()

		void print()
		{
			int i;
			int q = 1;
			while (q <= r)
			{
				cout << "[ ";
				for (i = 1; i <= c; i++)	//If the i is equal to the row then exit the loop
				{
					cout << mat[q][i] << " "; 
				} //End for
				q++;
				cout << "]\n";
			} //End while
		} // End print()

		matrix operator +(matrix b)
		{
			//matrix addition
			matrix ans(r, c);

			for (int i = 1; i <= r; i++)
			{
				for (int j = 1; j <= c; j++)
				{
					ans.mat[i][j] = mat[i][j] + b.mat[i][j];		//Add rows and cols of matrices
				}
			}
			return ans;
		}

		matrix operator -(matrix b)
		{
			matrix ans(r, c);

			for (int i = 1; i <= r; i++)
			{
				for (int j = 1; j <= c; j++)
				{
					ans.mat[i][j] = mat[i][j] - b.mat[i][j];		//subtract rows and cols of matrices
				}
			}

			return ans;
		}

		matrix operator *(matrix b)
		{
			matrix ans(r, b.c);	//Allows us to use rows and columns.
			float t;
			int i, j, k;

			for (i = 1; i <= r; i++)
			{
				for (j = 1; j <= c; j++)
				{
					t = 0;

					for (k = 1; k <= b.r; k++)
					{
						
						t += ((mat[i][k]) * (b.mat[k][j])); //multiplies matrices
					}

					ans.mat[i][j] = t;
				}
			}

			return ans;
		}

	


};		//ends matrix class


void main()
{ 

	matrix a(2, 2), b(2, 2), c;

	int ch = 0;
	do 
	{
		cout << "Welcome to the matrix program.\n";
		cout << "Choose one: \n";
		cout << "1) Input Matrix #1\n";
		cout << "2) Input Matrix #2\n";
		cout << "3) Add\n";
		cout << "4) Subtract\n";
		cout << "5) Multiply\n";
		cout << "6) Help\n";
		cout << "7) Exit\n";
		cin >> ch;

		if (ch == 1) 
		{
			a.input();
			a.print();		//get matrix a
		}
		else if (ch == 2) 
		{
			b.input();
			b.print();		//get matrix b
		}
		else if (ch == 3)
		{
			c = a + b;		//addtion
			c.print();
		}
		else if (ch == 4)

		{
			c = a - b;		//subtract
			c.print();
		}
		else if (ch == 5)
		{
			c = a * b;
			c.print();
		}
		else if (ch == 6)
		{
			system("cls");
			cout << "Enter matrix 1 and 2 then add, subtract, or multiply\n";
			cout << "NOTE: When multipling matrices that are not of the \n";
			cout << "same size you must enter them as the same size and \n";
			cout << "fill in the spaces with zeros(0)\n\n";
		}
		else
		{
			//Do not do anything
		}

	} 
	while (ch != 7);

}		//ends my main program

//End the matrix.cpp file