创建邻接表（AdjacencyList）

#include<stdio.h>
/*----------------------------邻接表的存储结构---------------------------*/
#define  MAX_VERTEX_NUM     20

typedef int  VRType;
typedef int  VertexType;

struct ArcNode {
   int      adjvex;
   struct ArcNode *nextarc;
   VRType   weight;
};

struct VexNode {
  VertexType    data;
  struct ArcNode  *firstarc;
};

typedef struct {
  struct VexNode  adjlist[MAX_VERTEX_NUM];
  int vexnum,arcnum;
}ALGraph;

/*============================================================================*/
int LocateVex(ALGraph *G,VertexType v)
{
  int i;
  for(i = 0;i < G->vexnum;i ++)
    if(v == (G->adjlist[i]).data )
       return i;
}

int CreateUDG(ALGraph *G)
{
   int i,j,k,kind=1;
   VRType weight=0;
   VertexType v1,v2;
   struct ArcNode *p;

   printf(" 1-Create DG/n 2-Create UDG/n CHOICE :");
   scanf("%d",&kind);

   printf("/n/n The Graph's number of Vertex :"); scanf("%d",&(G->vexnum));
   printf(" The Graph's number of Arcnum :"); scanf("%d",&(G->arcnum));
   printf("/n");
   for(i=0;i<G->vexnum;i++) {
      printf(" The Graph's %d Vertex's NAME:",i+1); scanf("%d",&(G->adjlist[i].data));
      G->adjlist[i].firstarc = NULL;
   }

   for(k=0;k<G->arcnum;k++)
   {
     printf("/n The %d Arc ./n",k+1);
     printf(" The tail vertex:");do{ scanf("%d",&v1);if((v1<=0)||(v1>G->vexnum))printf(" ERROR/n The tail vertex:"); }while((v1<=0)||(v1>G->vexnum));
     printf(" The head vertex:");do{ scanf("%d",&v2);if((v2<=0)||(v2>G->vexnum))printf(" ERROR/n The head vertex:"); }while((v2<=0)||(v2>G->vexnum));
     /*printf(" The arc  weight:");do{ scanf("%d",&weight); if(weight < 0) printf(" ERROR/n The arc  weight:"); }while(weight < 0);*/

     i = LocateVex(G,v1); j = LocateVex(G,v2);

     p = (struct ArcNode *)malloc(sizeof(struct ArcNode));
     p->adjvex = j;
     p->nextarc = G->adjlist[i].firstarc;
     p->weight = weight;
     G->adjlist[i].firstarc = p;

     if(2 == kind){
       p = (struct ArcNode *)malloc(sizeof(struct ArcNode));
       p->adjvex = i;
       p->nextarc = G->adjlist[j].firstarc;
       p->weight = weight;
       G->adjlist[j].firstarc = p;
     }
   }
   return 0;
}

void Prin_ALGraph(ALGraph *G)
{
   int k;
   struct ArcNode *p;

   printf("/n/n The Adjacenacy Vertex  =>/n/n");
   for(k = 0;k <G->vexnum;k ++)
   {
      p = G->adjlist[k].firstarc;
      printf("  /tVertex %d :",k+1);
      while( p != NULL ){  printf(" (%d,%d) ",G->adjlist[k].data,G->adjlist[p->adjvex].data);   p = p->nextarc; }
      printf("/n");
   }

}
/*------------------------------------------------------------------------------*/
int main()
{
   ALGraph G;
   CreateUDG(&G);
   Prin_ALGraph(&G);
   getch();
}