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

//graph head
typedef struct graphH {
    int count;
    struct graphV *firstV;
} HEAD;

//graph vertex
typedef struct graphV {
    struct graphV *nextV;
    char name;
    int degree;
    int processed;
    struct graphA *firstArc;
} VERTEX;

//graph arc
typedef struct graphA {
    struct graphV *destination;
    struct graphA *nextArc;
} ARC;

//prototype declarations
HEAD *createGraph (void);
HEAD *buildGraph (void);
void insertVertex (HEAD *pass_head, char x);

int main (void)
{
    HEAD *graph_head;

    graph_head=buildGraph();

    printf("%c", graph_head->firstV->name);
    printf("END\n");
    return 0;
}

// ------------------------------> createGraph
HEAD *createGraph (void)
{
    int i;
    HEAD *temp_head;
    temp_head = (HEAD *) malloc (sizeof (HEAD));

    if (temp_head)
    {
        temp_head->count=0;
        temp_head->firstV=NULL;
    }
    return temp_head;
}

// ------------------------------> buildGraph
HEAD *buildGraph (void)
{
    HEAD *temp_head;

    temp_head=createGraph();

    insertVertex(temp_head, 'c');
    /*insertVertex(temp_head, 'd');
    insertVertex(temp_head, 'e');
    insertVertex(temp_head, 'f');
    insertVertex(temp_head, 'g');
    insertVertex(temp_head, 'h');
    */
    return temp_head;
}

// ------------------------------> insertVertex
void insertVertex (HEAD *pass_head, char x)
{
    int i=0;
    VERTEX *hold_vertex;
    VERTEX *ptr_vertex;

    hold_vertex = (VERTEX *) malloc (sizeof (VERTEX));

    hold_vertex->nextV=NULL;
    hold_vertex->name=x;
    hold_vertex->degree=0;
    hold_vertex->processed=0;
    hold_vertex->firstArc=NULL;

    pass_head->count++;
    ptr_vertex=(VERTEX *)(pass_head->firstV);

    if (pass_head->count==1)
        ptr_vertex=hold_vertex;
    else
    {

    }
    return;
}

void insertArc (HEAD *pass_head, char *from_pass_name, char *to_pass_name)
{
    int i=0;
    ARC *hold_arc;
    VERTEX *ptr_vertex;

    hold_arc = (ARC *) malloc (sizeof(ARC));
    ptr_vertex=pass_head->firstV;

    for (i=0; i<pass_head->count; i++)
    {
        /*if (strcmp(from_pass_name, ptr_vertex->name) == 0)
        {

        }*/

        ptr_vertex=ptr_vertex->nextV;
    }

    return;
}