有向图的十字链表存储

/**
    有向图的十字链表存储
*/
#include <stdio.h>
#include <malloc.h>
#include <string.h>
#define N 5
#define MAX 50
typedef struct _ArcBox{
    int tailvex,headvex;///弧尾弧头顶点位置
    struct _ArcBox* out,*in;///指向下一个有相同弧头弧尾的结点
}ArcNode;
typedef struct _VexBox{
    char data[N];
    ArcNode* firstin,* firstout;
}VexNode;
typedef struct _graph{
    VexNode vex[MAX];
    int nume,numv;
}Graph;

int getIndex(Graph G,char s[]){
    for(int i = 0; i < G.numv; i++){
        if(strcmp(s,G.vex[i].data) == 0)
            return i;
    }
    return -1;
}

void create(Graph& G){
    printf("输入顶点与弧的个数:
");
    scanf("%d%d",&G.numv,&G.nume);
    ///初始化并输入顶点信息
    printf("输入顶点信息:
");
    for(int i = 0; i < G.numv; i++){
        G.vex[i].firstin = G.vex[i].firstout = NULL;
        scanf("%s",G.vex[i].data);
    }
    printf("输入弧信息:
");
    int u,v;
    char s[N],e[N];
    for(int i = 0; i < G.nume; i++){
        ArcNode* p = (ArcNode*)malloc(sizeof(ArcNode));
        p->in = p->out = NULL;
        scanf("%s%s",s,e);
        u = getIndex(G,s);
        v = getIndex(G,e);
        p->tailvex = u;
        p->headvex = v;
        p->out = G.vex[u].firstout;
        p->in = G.vex[v].firstin;
        G.vex[u].firstout = p;
        G.vex[v].firstin = p;
    }
}

void output(Graph G){
    ArcNode* p;
    for(int i = 0; i < G.numv; i++){
        printf("%4s ",G.vex[i].data);
        printf(" out:");
        p = G.vex[i].firstout;
        while(p != NULL){
//            printf("%d %d ",p->tailvex,p->headvex);
            printf("%4s%4s",G.vex[p->tailvex].data,G.vex[p->headvex].data);
            p = p->out;
        }
        printf(" in:");
        p = G.vex[i].firstin;
        while(p != NULL){
//            printf("%d %d ",p->tailvex,p->headvex);
            printf("%4s%4s",G.vex[p->tailvex].data,G.vex[p->headvex].data);
            p = p->in;
        }
        printf("
");
    }
}

int main(void){
    Graph G;
    create(G);
    output(G);
    return 0;
}