C program to print the sum of matrix boundary elements

1 2 3
4 5 6
7 8 9

1 2 3
4   6
7 8 9

for(i = 0; i<m; i++){
   for(j = 0; j<n; j++){
      if (i == 0 || j == 0 || i == n &ndash; 1 || j == n &ndash; 1){
         printf("%d ", mat[i][j]);
         sum = sum + mat[i][j];
      }
      else
         printf(" ");
      }
      printf("</p><p>");
}

#include<stdio.h>
#include<limits.h>
int main(){
   int m, n, sum = 0;
   printf("</p><p>Enter the order of the matrix : ");
   scanf("%d %d",&m,&n);
   int i, j;
   int mat[m][n];
   printf("</p><p>Input the matrix elements</p><p>");
   for(i = 0; i<m; i++){
      for(j = 0; j<n; j++)
      scanf("%d",&mat[i][j]);
   }
   printf("</p><p>Boundary Matrix</p><p>");
   for(i = 0; i<m; i++){
      for(j = 0; j<n; j++){
         if (i == 0 || j == 0 || i == n &ndash; 1 || j == n &ndash; 1){
            printf("%d ", mat[i][j]);
            sum = sum + mat[i][j];
         }
         else
         printf(" ");
      }
      printf("</p><p>");
   }
   printf("</p><p>Sum of boundary is %d", sum);
}

Enter the order of the matrix : 3 3
Input the matrix elements :
1 2 3
4 5 6
7 8 9
Boundary Matrix :
1 2 3
4 6
7 8 9
Sum of boundary is 40