还是这个图，对它用邻接矩阵dfs遍历

#include<bits/stdc++.h>
using namespace std;
#define MAXVEX 20
#define infinity 0x3f3f3f

typedef struct {
    char arcs[MAXVEX][MAXVEX]; // 边信息 
    char vex[MAXVEX];  //顶点信息 
    int vexnum;  //顶点数目 
    int arcnum;  //边数目 
    map<char,int> bar;//A ->1 B ->2
    map<int,char> foo;//1 ->A 2->B 就像英汉词典互译...
}AdjMatrix; //邻接矩阵 


void Create(AdjMatrix *G){
    int i,j,k,weight=1;
    //printf("请输入无向网中的顶点数和边数:\n");
    cin>>G->vexnum>>G->arcnum;
    //index from [1 , G->vexnum] 
    for(int i = 1;i <= G->vexnum;i++){
        for(int j = 1;j <= G->vexnum;j++){
            G->arcs[i][j] = '\0';
        }
    }
    //printf("请输入无向网中%d个顶点:\n",G->vexnum);
    //index form [1 , G->vexnum]; 
    for(int i = 1;i <=G->vexnum;i++){
        //printf("No.%d个顶点:顶点V",i);
        cin>>G->vex[i]; //A B C D 之类的顶点标识
        G->bar[G->vex[i]]=i; // bar[B]=2;
        G->foo[i]=G->vex[i]; // f[2] = B;
    }

    //printf("请输入无向无向网中%d条边:\n",G->arcnum);
    for(int k=0;k<G->arcnum;k++){
        //printf("\nNo.%d条边:\n 顶点V",k+1);
        char vex1,vex2;
        cin>>vex1;
        //printf("<------->顶点V");
        cin>>vex2;
        /* printf("权值: "); cin>>weight; */
        G->arcs[G->bar[vex1]][G->bar[vex2]] = weight;   //如果不是网，则赋值1 
        G->arcs[G->bar[vex2]][G->bar[vex1]] = weight;   //如果是有向图，删掉此句 
    }
}

int visit[MAXVEX]={0};
int FirstAdjVex(AdjMatrix g,int v0);
int NextAdjVex(AdjMatrix g,int v0,int w);

void dfs(AdjMatrix g,int v0){
    cout<<g.foo[v0];
    visit[v0] = 1;
    int w = FirstAdjVex(g,v0);   // v0的第一个邻接点 
    while(w != -1){
        if(!visit[w]){
            dfs(g,w);   
        }
        w =  NextAdjVex(g,v0,w);   // v0的下一个邻接点 
    }
}

void TraverseG(AdjMatrix g){
    for(int v = 1;v <= g.vexnum; v++){
        visit[v] = 0;
    }   
    for(int v = 1;v <= g.vexnum; v++){
        if(!visit[v]){
            dfs(g,v);
        }
    }
}

int FirstAdjVex(AdjMatrix g,int v0){
    int i;
    for(i = 1;i <= g.vexnum;i++){
        if(g.arcs[v0][i] !='\0'){
            break;
        }
    }
    if(i <= g.vexnum)
        return i;
    else
        return -1;
}

int NextAdjVex(AdjMatrix g,int v0,int w){
    int i=w+1;
    for(;i <= g.vexnum; i++){
        if(g.arcs[v0][i] != '\0'){
            break;
        }
    }
    if(i <= g.vexnum)
        return i;
    else
        return -1;
}
int main(){
    //freopen("in5.txt","r",stdin);
    //freopen("out.txt","w",stdout);
    AdjMatrix G;
    Create(&G);
    TraverseG(G);

} 

in5.txt

8 9 
A B C D E F G H 
A B 
A C 
B D 
B E 
C F 
C G
D H
F G

out.txt

A B D H E C F G