Depth First Search

#include <stdio.h>
#include <stdlib.h>
struct node
{
  int vertex;
  struct node *next;
}*g[50];
int visited[50]={0};
void insert(int x, int y){
    struct node *p,*q = (struct node *) malloc(sizeof(struct node));
    q->vertex = y; q->next = NULL;
    if(g[x] == NULL) g[x] = q;
    else{
        p = g[x];
        while(p->next) p = p->next;
        p->next = q;
    }
}
void DFS(int i)
{
    struct node *p;
    printf("%d  ", i);
    p = g[i];
    visited[i] = 1;
    while(p != NULL){
        i=p->vertex;
        if(!visited[i]) DFS(i);
        p = p->next;
    }
}
int main()
{
    int i, x, y, edge, n;
    printf("\nEnter number of vertices: ");
    scanf("%d", &n);
    for(i=0; i<n; i++) g[i]=NULL;
    printf("\nEnter number of edges: ");
    scanf("%d", &edge);
    for(i=0;i<edge;i++){
        printf("\nEnter an edge(u,v): ");
        scanf("%d %d", &x,&y);
        insert(x, y);
        insert(y, x);
    }
    printf("\nEnter a value: ");
    scanf("%d", &n);
    DFS(n);
}