邻接表创建无向图c语言代码

以下是使用邻接表创建无向图的 C 语言代码：

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

struct Node {
    int data;
    struct Node* next;
};

struct Graph {
    int numVertices;
    struct Node** adjLists;
};

struct Node* createNode(int data) {
    struct Node* newNode = (struct Node*)malloc(sizeof(struct Node));
    newNode->data = data;
    newNode->next = NULL;
    return newNode;
}

struct Graph* createGraph(int vertices) {
    struct Graph* graph = (struct Graph*)malloc(sizeof(struct Graph));
    graph->numVertices = vertices;

    graph->adjLists = (struct Node**)malloc(vertices * sizeof(struct Node*));

    int i;
    for (i = 0; i < vertices; i++) {
        graph->adjLists[i] = NULL;
    }

    return graph;
}

void addEdge(struct Graph* graph, int src, int dest) {
    // Add edge from src to dest
    struct Node* newNode = createNode(dest);
    newNode->next = graph->adjLists[src];
    graph->adjLists[src] = newNode;

    // Add edge from dest to src
    newNode = createNode(src);
    newNode->next = graph->adjLists[dest];
    graph->adjLists[dest] = newNode;
}

void printGraph(struct Graph* graph) {
    int v;
    for (v = 0; v < graph->numVertices; v++) {
        struct Node* temp = graph->adjLists[v];
        printf("\n Adjacency list of vertex %d\n head ", v);
        while (temp) {
            printf("-> %d", temp->data);
            temp = temp->next;
        }
        printf("\n");
    }
}

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

    printGraph(graph);

    return 0;
}

在上面的代码中，我们首先定义了一个 `Node` 结构体来表示节点，其中包括节点的数据和指向下一个节点的指针。然后，我们定义了一个 `Graph` 结构体来表示无向图，其中包括节点数量和一个指向邻接表的指针数组。`createNode` 函数用于创建新节点，`createGraph` 函数用于创建无向图并初始化邻接表，`addEdge` 函数用于添加边，`printGraph` 函数用于打印邻接表。在 `main` 函数中，我们创建一个包含 4 个节点的无向图，并添加 4 条边。最后，我们打印出邻接表来验证图是否正确创建。