用c语言写一个无向图的邻接表

下面是用C语言实现无向图的邻接表：

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

// 定义一个邻接表节点
struct AdjListNode {
    int dest;
    struct AdjListNode* next;
};

// 定义邻接表头结点
struct AdjList {
    struct AdjListNode* head;
};

// 定义图结构
struct Graph {
    int V; // 顶点数量
    struct AdjList* array;
};

// 创建一个邻接表节点
struct AdjListNode* newAdjListNode(int dest) {
    struct AdjListNode* newNode = (struct AdjListNode*)malloc(sizeof(struct AdjListNode));
    newNode->dest = dest;
    newNode->next = NULL;
    return newNode;
}

// 创建图
struct Graph* createGraph(int V) {
    struct Graph* graph = (struct Graph*)malloc(sizeof(struct Graph));
    graph->V = V;
    graph->array = (struct AdjList*)malloc(V * sizeof(struct AdjList));

    for (int i = 0; i < V; ++i) {
        graph->array[i].head = NULL;
    }
    return graph;
}

// 添加边到无向图中
void addEdge(struct Graph* graph, int src, int dest) {
    // 添加一条边从源到目标
    struct AdjListNode* newNode = newAdjListNode(dest);
    newNode->next = graph->array[src].head;
    graph->array[src].head = newNode;

    // 添加一条边从目标到源，因为是无向图
    newNode = newAdjListNode(src);
    newNode->next = graph->array[dest].head;
    graph->array[dest].head = newNode;
}

// 打印图的邻接表表示
void printGraph(struct Graph* graph) {
    for (int i = 0; i < graph->V; ++i) {
        struct AdjListNode* head = graph->array[i].head;
        printf("\n顶点 %d 的邻接表为\nhead ", i);
        while (head) {
            printf("-> %d", head->dest);
            head = head->next;
        }
        printf("\n");
    }
}

int main() {
    int V = 5;
    struct Graph* graph = createGraph(V);
    addEdge(graph, 0, 1);
    addEdge(graph, 0, 4);
    addEdge(graph, 1, 2);
    addEdge(graph, 1, 3);
    addEdge(graph, 1, 4);
    addEdge(graph, 2, 3);
    addEdge(graph, 3, 4);

    printGraph(graph);

    return 0;
}

输出结果为：

顶点 0 的邻接表为
head -> 4 -> 1

顶点 1 的邻接表为
head -> 4 -> 3 -> 2 -> 0

顶点 2 的邻接表为
head -> 3 -> 1

顶点 3 的邻接表为
head -> 4 -> 2 -> 1

顶点 4 的邻接表为
head -> 3 -> 1 -> 0