c语言实现图的深度优先遍历和广度优先遍历算法。

深度优先遍历（DFS）和广度优先遍历（BFS）是图的两种常见遍历算法。下面是使用C语言实现DFS和BFS的示例代码。

假设图用邻接表存储，每个节点的邻接点用链表表示。

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

#define MAX_N 100

typedef struct node {
    int v;  // 邻接点的编号
    struct node *next;
} node_t;

typedef struct graph {
    int n;  // 节点个数
    node_t *adj[MAX_N];  // 邻接表
} graph_t;

// 深度优先遍历
void dfs(graph_t *g, int v, int visited[]) {
    printf("%d ", v);
    visited[v] = 1;
    node_t *p = g->adj[v];
    while (p) {
        if (!visited[p->v]) {
            dfs(g, p->v, visited);
        }
        p = p->next;
    }
}

// 广度优先遍历
void bfs(graph_t *g, int v, int visited[]) {
    int queue[MAX_N], head = 0, tail = 0;
    queue[tail++] = v;
    visited[v] = 1;
    while (head < tail) {
        int u = queue[head++];
        printf("%d ", u);
        node_t *p = g->adj[u];
        while (p) {
            if (!visited[p->v]) {
                visited[p->v] = 1;
                queue[tail++] = p->v;
            }
            p = p->next;
        }
    }
}

int main() {
    int n, m, i, u, v;
    graph_t *g = (graph_t*) malloc(sizeof(graph_t));
    scanf("%d%d", &n, &m);

    // 初始化图
    g->n = n;
    for (i = 0; i < n; i++) {
        g->adj[i] = NULL;
    }

    // 读入边
    for (i = 0; i < m; i++) {
        scanf("%d%d", &u, &v);
        node_t *p = (node_t*) malloc(sizeof(node_t));
        p->v = v;
        p->next = g->adj[u];
        g->adj[u] = p;

        p = (node_t*) malloc(sizeof(node_t));
        p->v = u;
        p->next = g->adj[v];
        g->adj[v] = p;
    }

    // 深度优先遍历
    int visited[MAX_N] = {0};
    dfs(g, 0, visited);
    printf("\n");

    // 广度优先遍历
    for (i = 0; i < n; i++) {
        visited[i] = 0;
    }
    bfs(g, 0, visited);
    printf("\n");

    // 释放内存
    for (i = 0; i < n; i++) {
        node_t *p = g->adj[i];
        while (p) {
            node_t *tmp = p;
            p = p->next;
            free(tmp);
        }
    }
    free(g);

    return 0;
}

输入格式为：

节点个数 边数
边1起点 边1终点
边2起点 边2终点
...

例如：

4 3
0 1
1 2
2 3

输出为：

0 1 2 3
0 1 2 3