邻接表创建无向图c语言代码

以下是邻接表创建无向图的 C 语言代码：

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

struct node {
    int vertex;
    struct node* next;
};

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

struct node* createNode(int v) {
    struct node* newNode = malloc(sizeof(struct node));
    newNode->vertex = v;
    newNode->next = NULL;
    return newNode;
}

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

    graph->adjLists = 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) {
    struct node* newNode = createNode(dest);
    newNode->next = graph->adjLists[src];
    graph->adjLists[src] = newNode;

    newNode = createNode(src);
    newNode->next = graph->adjLists[dest];
    graph->adjLists[dest] = newNode;
}

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

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

    displayGraph(graph);

    return 0;
}

这个代码创建了一个包含 4 个顶点的无向图，并且使用邻接表来表示它。`createNode` 函数创建一个新节点，`createGraph` 函数创建一个新图，`addEdge` 函数向图中添加一条边，`displayGraph` 函数打印图的邻接表表示形式。这个程序的输出如下：

 Adjacency list of vertex 0
  2 -> 1 -> NULL

 Adjacency list of vertex 1
  2 -> 0 -> NULL

 Adjacency list of vertex 2
  3 -> 1 -> 0 -> NULL

 Adjacency list of vertex 3
  2 -> NULL

这个输出表示了每个顶点的邻接列表，其中每个列表包含与该顶点相邻的所有顶点。例如，顶点 0 的邻接列表包含顶点 1 和 2，而顶点 2 的邻接列表包含顶点 1、0 和 3。这个程序可以根据需要进行修改以创建任何大小和形状的无向图。