2d diagonal sum

#include <iostream>
#include <bits/stdc++.h>

using namespace std;

int main()
{
    int arr[4][4], row ,col,r_d=0,l_d=0;
    for(col=0;col<4; col++){

        for (row=0;row<4;row++){
            cout<<"enter the "<<col<<" x "<<row<<" enter :";
            cin>> arr[col][row];

        }
    }
    cout<<"the 4x4 matrix enter by the user :"<< endl;


    for(col=0;col<4; col++){
        cout<<endl;
        for (row=0;row<4;row++){
            cout<<setw(4)<<arr[col][row];

        }
    }
    cout<<endl;

    for(col=0;col<4; col++){
        cout<<endl;
        for (row=0;row<4;row++){
           if(col==row){
             r_d=r_d + arr[col][row];
            cout<<arr[col][row]<<" ";
           }

        }
    }
    cout<<endl;
    cout<<" right diagonal : "<<r_d;

    cout<<endl;
int s=3;
    for(col=0;col<4; col++){
        cout<<endl;
        for (row=0;row<4;row++){
           if(row==s){
             l_d=l_d + arr[col][row];
            cout<<arr[col][row]<<" ";
           }
        }
        s--;
    }

    cout<<endl;
    cout<<" left diagonal : "<<l_d;
     cout<<endl;
    cout<<"sum of diagonals : "<<r_d+l_d;

    return 0;
}