ضرب مصفوفتين

#include <iostream>
using namespace std ;
int main ()
{
 int i,j,k,sum ;
 int a[2][2],b[2][2] ;
 for (i=0; i<2; i++)
 { 
   for (j=0; j<2; j++)
   {
    cout << "Enter for " << "a[" << i << "][" << j << "]" << " element";
    cin >> a[j];
   }
  }

  cout << endl << endl;
  for (i=0; i<2; i++){ // this is for b
   for (j=0; j<2; j++){
    cout << "Enter for" << "b[" << i << "][" << j << "]" << " element" ;
    cin >> b[j];
   }
  }
  cout << "Now you see here that you typed for Matrix a" << endl << endl;
  cout << "********************************************" << endl << endl;
  for (i=0; i<2; i++)
  {
   for (j=0; j<2; j++)
   {
    cout << a[j] << '\t';
   }
   cout << endl << endl ;
  }
  cout << endl << endl;
  cout << "Now you see here that you typed for Matrix b" << endl<<endl;
  cout << "*********************************************" <<endl << endl;
  for (i=0; i<2; i++)
  {
   for (j=0; j<2; j++)
   {
    cout << b[j] << '\t';
   }
   cout << endl << endl;
  }
  cout << "\n";
  cout << "Now you see here the multiplication of Matrix a and b" << endl<< endl ;
  cout << "+******************************************************+" << endl << endl ;
  for (i =0; i<2; i++)
  {
   for (j=0; j<2; j++)
   {
    sum = 0; 
    for (k=0; k<2; k++){
     sum = sum + a[k] * b[k][j];
    }
    cout << sum << '\t';
   }
   cout << endl <<  endl;
   }
  return 0;
}

الكود شغال مية المية

لكن الاستفسار

  cout << "Now you see here the multiplication of Matrix a and b" << endl<< endl ;
  cout << "+******************************************************+" << endl << endl ;
  for (i =0; i<2; i++)
  {
   for (j=0; j<2; j++)
   {
    sum = 0; 
    for (k=0; k<2; k++){
     sum = sum + a[k] * b[k][j];
    }
    cout << sum << '\t';
   }
   cout << endl <<  endl;
   }
  return 0;

كيفية عمل الكود هنا كيف سيسير البرنامج ؟