Matrix - Sum of Edge Elements

                                                               

 The input elements of R*C matrix is passed as the input (R is the number of rows and C is the number of columns in the matrix. The program must print the sum S of the elements along the edge of the matrix.

Input Format:
The first line contains R and C separated by a space..
Next R lines contain C values each, with the values separated by a space.

Output Format:
The first line contains S.

Boundary Conditions:
2 <= R, C <= 100
1 <= Matrix Cell Value <= 1000

Example Input/Output 1:
Input:
5 3
1 2 3
4 5 6
7 8 9
5 5 5
2 2 2

Output:
48

Example Input/Output 2:
Input:
3 3
100 200 300
400 500 600
700 800 900

Output:
4000

C code:

#include<stdio.h>

#include <stdlib.h>

int main()

{

int r,c;

scanf("%d%d",&r,&c);

int t,s=0;

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

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

{

 scanf("%d",&t);

 if(i==0||i==r-1||j==0||j==c-1)

 s+=t;

}

printf("%d",s);

}