Question

In C++ write a function to find a product of two matrices using arrays. The function should be general and should accept any size matrices.

Answer 1

The Program Code is :

///Cpp program for Product of two Arrays
/// Using Function
#include<iostream>
using namespace std;
void matrix_Multilication(int **m1,int **m2,int r1,int c1,int c2,int r2)
{
                        ///Function Definition
    int i,j,k;
    int **m3;
    int sum = 0;

    m3=new int *[r1];
    for(i = 0;i < r1 ;i++)
    {
        m3[i]=new int[c2];///Dynamic memory allocation for Matrix3
    }

     cout<<"The Matrix 1 is :"<<endl;
     for(i = 0; i < r1; i++)
     {
      for(j = 0; j < c1; j++)
      {
          cout<<m1[i][j]<<"\t";///It will display Matrix1 Elements
      }
      cout<<endl;
    }

    cout<<"The Matrix 2 is :"<<endl;
    for(i = 0; i < r2; i++)
    {
    for(j = 0; j < c2; j++)
      {
          cout<<m1[i][j]<<"\t";///It will display Matrix2 Elements
      }
      cout<<endl;

    }
/// Matrix Multiplication logic
    for(i = 0; i < r1; ++i)
    {
        for(j = 0; j < c2; ++j)
        {
            for(k = 0; k < c1; ++k)
            {
               sum += m1[i][k] * m2[k][j];
            }
            m3[i][j] = sum;
            sum = 0;
        }
    }

cout<<"The Product of Matrix 1 and Matrix2 is :"<<endl;
for(i = 0; i < r1; i++)
{
      for(j = 0; j < c2; j++)
      {
          cout<<m3[i][j]<<"\t";///It will display Product Elements
      }
      cout<<endl;

    }
}

int main()
{
int **m1; ///Double Pointer m1 for 2D Array
int **m2; ///Double Pointer m2 for 2D Array

int i,j,k,r1,c1,r2,c2;
cout<<"Enter Number of Rows and Columns of Matrix 1 "<<endl;
cin>>r1>>c1;

cout<<"Enter Number of Rows and Columns of Matrix 2 "<<endl;
cin>>r2>>c2;

while(c1 != r2)///It will check Matrix Multiplication is Possible or Not
{
      cout<<" Error : ";
      cout<<"Column of matrix 1 and Rows of matrix 2 Must be Equal "<<endl;
      cout<<"Again : "<<endl;

      cout<<"Enter Number of Rows and Columns of Matrix 1 "<<endl;
      cin>>r1>>c1;

      cout<<"Enter Number of Rows and Columns of Matrix 2 "<<endl;
      cin>>r2>>c2;

}

m1=new int *[r1];
    for(i = 0;i < r1 ;i++)
    {
         m1[i]=new int[c1];///Dynamic memory allocation for Matrix1

    }
   cout<<"Enter Matrix1 : "<<r1*c1<<" values"<<endl;

   for(i = 0; i < r1; i++)
{
      for(j = 0; j < c1; j++)
      {
          cin>>m1[i][j];/// It will Read the matrix1 Elements
      }
}
    m2=new int *[r2];
    for(i = 0;i < r2 ;i++)
    {
         m2[i]=new int[c2]; ///Dynamic memory allocation for Matrix2
    }

   cout<<"Enter Matrix2 : "<<r2*c2<<" values"<<endl;
for(i = 0; i < r2; i++)
{
      for(j = 0; j < c2; j++)
      {
          cin>>m2[i][j];/// It will Read the matrix2 Elements
      }
}
matrix_Multilication(m1,m2,r1,c1,c2,r2);///Function Calling

return 0;
}