Graph and Searching Implementation

				
					#include <stdio.h>
int a[20][20], reach[20], n;
void dfs(int v)
{
     int i;
     reach[v] = 1;
     for (i = 1; i <= n; i++)
     {
          if (a[v][i] && !reach[i])
          {
               printf("\n %d->%d", v, i);
               dfs(i);
          }
     }
}
void main()
{
     int i, j, count = 0;
     printf("\n Enter number of vertices");
     scanf("%d", &n);
     for (i = 1; i <= n; i++)
     {
          reach[i] = 0;
          for (j = 1; j <= n; j++)
               a[i][j] = 0;
     }
     printf("\nEnter adjacency matrix:\n");
     for (i = 1; i <= n; i++)
          for (j = 1; j <= n; j++)
               scanf("%d", &a[i][j]);
     dfs(1);
     printf("\n");
     for (i = 1; i <= n; i++)
     {
          if (reach[i])
               count++;
     }
     if (count == n)
          printf("\n Graph is connected");
     else
          printf("\n Graph is not connected");
}