建立图并输出，输入1是有向图，输入0是无向图用C语言实现

以下是用 C 语言实现建立图并输出的示例代码，包括有向图和无向图：

有向图：

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

#define MAX_VERTICES 100

typedef struct GraphNode {
    int vertex;
    struct GraphNode *next;
} GraphNode;

typedef struct {
    GraphNode *head;
} Vertex;

typedef struct {
    Vertex vertices[MAX_VERTICES];
    int vertex_count;
} Graph;

void init_graph(Graph *g) {
    g->vertex_count = 0;
}

void add_vertex(Graph *g) {
    if (g->vertex_count < MAX_VERTICES) {
        g->vertices[g->vertex_count++].head = NULL;
    }
    else {
        printf("Graph full, cannot add vertex.\n");
    }
}

void add_edge(Graph *g, int src, int dest) {
    if (src >= g->vertex_count || dest >= g->vertex_count) {
        printf("Vertex does not exist.\n");
    }
    else {
        GraphNode *new_node = (GraphNode*)malloc(sizeof(GraphNode));
        new_node->vertex = dest;
        new_node->next = g->vertices[src].head;
        g->vertices[src].head = new_node;
    }
}

void display_graph(Graph *g) {
    int i;
    for (i = 0; i < g->vertex_count; ++i) {
        GraphNode *ptr = g->vertices[i].head;
        printf("Adjacency list of vertex %d:\n", i);
        while (ptr != NULL) {
            printf("%d -> ", ptr->vertex);
            ptr = ptr->next;
        }
        printf("NULL\n");
    }
}

int main() {
    Graph g;
    int i, src, dest, edges, vertices;

    init_graph(&g);

    printf("Enter the number of vertices: ");
    scanf("%d", &vertices);

    for (i = 0; i < vertices; ++i) {
        add_vertex(&g);
    }

    printf("Enter the number of edges: ");
    scanf("%d", &edges);

    for (i = 0; i < edges; ++i) {
        printf("Enter edge %d (src dest): ", i+1);
        scanf("%d %d", &src, &dest);
        add_edge(&g, src, dest);
    }

    display_graph(&g);

    return 0;
}

无向图：

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

#define MAX_VERTICES 100

typedef struct GraphNode {
    int vertex;
    struct GraphNode *next;
} GraphNode;

typedef struct {
    GraphNode *head;
} Vertex;

typedef struct {
    Vertex vertices[MAX_VERTICES];
    int vertex_count;
} Graph;

void init_graph(Graph *g) {
    g->vertex_count = 0;
}

void add_vertex(Graph *g) {
    if (g->vertex_count < MAX_VERTICES) {
        g->vertices[g->vertex_count++].head = NULL;
    }
    else {
        printf("Graph full, cannot add vertex.\n");
    }
}

void add_edge(Graph *g, int src, int dest) {
    if (src >= g->vertex_count || dest >= g->vertex_count) {
        printf("Vertex does not exist.\n");
    }
    else {
        GraphNode *new_node = (GraphNode*)malloc(sizeof(GraphNode));
        new_node->vertex = dest;
        new_node->next = g->vertices[src].head;
        g->vertices[src].head = new_node;

        new_node = (GraphNode*)malloc(sizeof(GraphNode));
        new_node->vertex = src;
        new_node->next = g->vertices[dest].head;
        g->vertices[dest].head = new_node;
    }
}

void display_graph(Graph *g) {
    int i;
    for (i = 0; i < g->vertex_count; ++i) {
        GraphNode *ptr = g->vertices[i].head;
        printf("Adjacency list of vertex %d:\n", i);
        while (ptr != NULL) {
            printf("%d -> ", ptr->vertex);
            ptr = ptr->next;
        }
        printf("NULL\n");
    }
}

int main() {
    Graph g;
    int i, src, dest, edges, vertices;

    init_graph(&g);

    printf("Enter the number of vertices: ");
    scanf("%d", &vertices);

    for (i = 0; i < vertices; ++i) {
        add_vertex(&g);
    }

    printf("Enter the number of edges: ");
    scanf("%d", &edges);

    for (i = 0; i < edges; ++i) {
        printf("Enter edge %d (src dest): ", i+1);
        scanf("%d %d", &src, &dest);
        add_edge(&g, src, dest);
    }

    display_graph(&g);

    return 0;
}