2D Matrix - Elements Adjacent Sum

                 2D Matrix - Elements Adjacent Sum

                                                       

Given a matrix of R rows and C columns, for each element print the sum of the adjacent elements.

Input Format:
The first line contains R
The second line contains C
Next R lines each contains C values separated by a space

Output Format:
R lines each containing C values which represent the sum of the adjacent elements.

Boundary Conditions:
2 <= R,C <= 50
1 <= Matrix Elements <= 100

Example Input/Output 1:
Input:
5 5
11 11 5 6 18
12 4 16 9 19
5 20 7 5 2
20 19 7 2 11
16 18 5 16 17

Output:
11 16 17 23 6
4 28 13 35 9
20 12 25 9 5
19 27 21 18 2
18 21 34 22 16

Code:

#include <iostream>

using namespace std;

int main(int argc, char** argv)

{

int i,j,r,c,sum=0;

cin>>r>>c;

int arr[r][c];

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

        for(j=0;j<c;j++)

            cin>>arr[i][j];

   

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

    {

        for(j=0;j<c;j++)

            {

                if(j==0)

                    sum=arr[i][j+1];

                else if(j==c-1)

                    sum=arr[i][j-1];

                else

                    sum=arr[i][j-1]+arr[i][j+1];

                cout<<sum<<" ";

            }

        cout<<"\n";

    }

}