#include<iostream> #define OK 1 #define ERROR 0 #define OVERFLOW -2 #define MVNum 100 //最大顶点数 using namespace std; typedef struct ArcNode {//边结点 int adjvex; //邻接点域：该边所指向的顶点的位置 int data; //数据域：存储和边相关的信息 struct ArcNode* nextarc; //链域：指向下一条边的指针 }ArcNode; typedef struct VNode {//顶点信息 int data; //顶点结点的数据域 ArcNode *firstarc; //链域：指向第一条依附该顶点的边的指针 }VNode,AdjList[MVNum]; //AdjList表示邻接表类型 typedef struct {//邻接表 AdjList vertices; int vexnum,arcnum; //图的当前顶点数和边数 }ALGragh; int CreateUDG(ALGragh &G,int vexnum,int arcnum) {//采用邻接表表示法，创建无向图G } int InsertVex(ALGragh &G) {//在以邻接表形式存储的无向图G上插入顶点v } int PrintGraph(ALGragh G) {//输出图G }补全代码

下面是补全代码的示例：

#include<iostream>
#define OK 1
#define ERROR 0
#define OVERFLOW -2
#define MVNum 100     //最大顶点数
using namespace std;

typedef struct ArcNode {//边结点
    int adjvex;                //邻接点域：该边所指向的顶点的位置
    int data;                  //数据域：存储和边相关的信息
    struct ArcNode* nextarc;   //链域：指向下一条边的指针
}ArcNode;

typedef struct VNode {//顶点信息
    int data;              //顶点结点的数据域
    ArcNode *firstarc;     //链域：指向第一条依附该顶点的边的指针
}VNode,AdjList[MVNum];     //AdjList表示邻接表类型

typedef struct {//邻接表
    AdjList vertices; 
    int vexnum,arcnum;    //图的当前顶点数和边数
}ALGragh;

int CreateUDG(ALGragh &G,int vexnum,int arcnum) {//采用邻接表表示法，创建无向图G
    G.vexnum = vexnum;
    G.arcnum = arcnum;
    for(int i=0;i<G.vexnum;i++){
        G.vertices[i].data = i+1; //顶点信息
        G.vertices[i].firstarc = NULL; //边表头指针
    }
    for(int k=1;k<=G.arcnum;k++){
        int i,j;
        cout << "请输入第" << k << "条边的两个顶点的编号(空格分隔):" << endl;
        cin >> i >> j;
        //插入边<i,j>
        ArcNode *p = new ArcNode;
        p->adjvex = j-1;
        p->nextarc = G.vertices[i-1].firstarc;
        G.vertices[i-1].firstarc = p;
        //插入边<j,i>
        ArcNode *q = new ArcNode;
        q->adjvex = i-1;
        q->nextarc = G.vertices[j-1].firstarc;
        G.vertices[j-1].firstarc = q;
    }
    return OK;
}

int InsertVex(ALGragh &G) {//在以邻接表形式存储的无向图G上插入顶点v
    if(G.vexnum == MVNum){
        cout << "图的顶点数已达到最大值，无法插入！" << endl;
        return ERROR;
    }
    G.vexnum++;
    G.vertices[G.vexnum-1].data = G.vexnum;
    G.vertices[G.vexnum-1].firstarc = NULL; //边表头指针
    return OK;
}

int PrintGraph(ALGragh G) {//输出图G
    cout << "图的邻接表表示如下：" << endl;
    for(int i=0;i<G.vexnum;i++){
        cout << "顶点" << G.vertices[i].data << ": ";
        ArcNode *p = G.vertices[i].firstarc;
        while(p != NULL){
            cout << p->adjvex+1 << "->";
            p = p->nextarc;
        }
        cout << "NULL" << endl;
    }
    return OK;
}

int main(){
    ALGragh G;
    int vexnum,arcnum;
    cout << "请输入无向图的顶点数和边数(空格分隔):" << endl;
    cin >> vexnum >> arcnum;
    CreateUDG(G,vexnum,arcnum);
    PrintGraph(G);
    InsertVex(G);
    PrintGraph(G);
    return 0;
}

其中，CreateUDG函数用于创建无向图，InsertVex函数用于在无向图中插入新的顶点，PrintGraph函数用于输出无向图的邻接表表示。