用C语言编写.给定一个无向连通图G，采用深度优先搜索方式访问图中节点，并输出。

以下是用C语言编写的深度优先搜索无向连通图并输出的代码：

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

#define MAX_VERTEX_NUM 100

typedef struct ArcNode {
    int adjvex;
    struct ArcNode *nextarc;
} ArcNode;

typedef struct VNode {
    int data;
    ArcNode *firstarc;
} VNode, AdjList[MAX_VERTEX_NUM];

typedef struct {
    AdjList vertices;
    int vexnum, arcnum;
} ALGraph;

void DFS(ALGraph *G, int v, int *visited) {
    visited[v] = 1;
    printf("%d ", G->vertices[v].data);
    ArcNode *p = G->vertices[v].firstarc;
    while (p) {
        if (!visited[p->adjvex]) {
            DFS(G, p->adjvex, visited);
        }
        p = p->nextarc;
    }
}

void DFSTraverse(ALGraph *G) {
    int visited[MAX_VERTEX_NUM] = {0};
    for (int i = 0; i < G->vexnum; i++) {
        if (!visited[i]) {
            DFS(G, i, visited);
        }
    }
}

ALGraph* InitGraph(ALGraph* g, int number) {
    g = (ALGraph*)malloc(sizeof(ALGraph));
    g->vexnum = number;
    g->arcnum = 0;
    for (int i = 0; i < number; i++) {
        g->vertices[i].data = i;
        g->vertices[i].firstarc = NULL;
    }
    return g;
}

void AddEdge(ALGraph* g, int u, int v) {
    ArcNode *p = (ArcNode*)malloc(sizeof(ArcNode));
    p->adjvex = v;
    p->nextarc = g->vertices[u].firstarc;
    g->vertices[u].firstarc = p;
}

int main() {
    int n = 5;
    int edges[3][2] = {{0, 1}, {1, 2}, {3, 4}};
    ALGraph *G = InitGraph(G, n);
    for (int i = 0; i < 3; i++) {
        AddEdge(G, edges[i][0], edges[i][1]);
        AddEdge(G, edges[i][1], edges[i][0]);
    }
    DFSTraverse(G);
    return 0;
}