Implement DFS ( Depth First Search) in C || With simple code

  // write a program in c to implement DFS (Depth  First Search)

  #include <stdio.h>
  #include <stdlib.h>

  typedef struct node
  {
      struct node *next;
      int vertex;
  } node;
  node *G[20];
  //heads of linked list
  int visited[20];
  int n;
  void graph();
  //create adjacency list
  void insert(int, int);
  //insert an edge (vi,vj) in te adjacency list
  void DFS(int);
  void main()
  {
    int i;
    graph();
    //initialised visited to 0

    for (i = 0; i < n; i++)
        visited[i] = 0;
    DFS(0);
  }
  void DFS(int i)
 {
    node *p;

    printf("\n%d", i);
    p = G[i];
    visited[i] = 1;
    while (p != NULL)
    {
        i = p->vertex;

        if (!visited[i])
            DFS(i);
        p = p->next;
     }
  }
  void graph()
  {
    int i, vi, vj, no_of_edges;
    printf("Enter number of vertices:\n");

    scanf("%d", &n);
    //initialise G[] with a null

    for (i = 0; i < n; i++)
    {
        G[i] = NULL;
        //read edges and insert them in G[]

        printf("Enter number of edges:");
        scanf("%d", &no_of_edges);
        for (i = 0; i < no_of_edges; i++)
        {
            printf("Enter an edge(u,v):");
            scanf("%d%d", &vi, &vj);
            insert(vi, vj);
        }
    }
  }
  void insert(int vi, int vj)
  {
    node *p, *q;

    //acquire memory for the new node
    q = (node *)malloc(sizeof(node));
    q->vertex = vj;
    q->next = NULL;
    //insert the node in the linked list number vi
    if (G[vi] == NULL)
        G[vi] = q;
    else
    {
        //go to end of the linked list
        p = G[vi];

        while (p->next != NULL)
            p = p->next;
        p->next = q;
    }
  }  

When the above program is executed, it produces following results --<\b>
OUTPUT NO :-

    Enter number of vertices:
   8
   Enter number of edges:10
   Enter an edge(u,v):0 1
   Enter an edge(u,v):0 2
   Enter an edge(u,v):0 3
   Enter an edge(u,v):0 4
   Enter an edge(u,v):1 5
   Enter an edge(u,v):2 5
   Enter an edge(u,v):3 6
   Enter an edge(u,v):4 6
   Enter an edge(u,v):5 7
   Enter an edge(u,v):6 7

   0
   1
   5
   7
   2
   3
   6
   4