用C语言代码编写函数，构造以邻接表表示的图；

可以使用以下代码来构造以邻接表表示的图：

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

#define MAXV 1000

typedef struct edgenode {
    int y;
    int weight;
    struct edgenode *next;
} edgenode;

typedef struct {
    edgenode *edges[MAXV + 1];
    int degree[MAXV + 1];
    int nvertices;
    int nedges;
    int directed;
} graph;

void initialize_graph(graph *g, int directed) {
    int i;
    g->nvertices = 0;
    g->nedges = 0;
    g->directed = directed;
    for (i = 1; i <= MAXV; i++) {
        g->degree[i] = 0;
        g->edges[i] = NULL;
    }
}

void insert_edge(graph *g, int x, int y, int weight, int directed) {
    edgenode *p;
    p = malloc(sizeof(edgenode));
    p->weight = weight;
    p->y = y;
    p->next = g->edges[x];
    g->edges[x] = p;
    g->degree[x]++;
    if (directed == 0) {
        insert_edge(g, y, x, weight, 1);
    } else {
        g->nedges++;
    }
}

void read_graph(graph *g, int directed) {
    int i, m, x, y, weight;
    initialize_graph(g, directed);
    scanf("%d %d", &(g->nvertices), &m);
    for (i = 1; i <= m; i++) {
        scanf("%d %d %d", &x, &y, &weight);
        insert_edge(g, x, y, weight, directed);
    }
}

void print_graph(graph *g) {
    int i;
    edgenode *p;
    for (i = 1; i <= g->nvertices; i++) {
        printf("%d: ", i);
        p = g->edges[i];
        while (p != NULL) {
            printf(" %d(%d)", p->y, p->weight);
            p = p->next;
        }
        printf("\n");
    }
}

int main() {
    graph g;
    read_graph(&g, 0);
    print_graph(&g);
    return 0;
}

这个代码使用了邻接表来表示图，其中 `edgenode` 结构体表示一条边，`graph` 结构体表示整个图。在 `initialize_graph` 函数中，初始化了图的各个属性；在 `insert_edge` 函数中，插入了一条边；在 `read_graph` 函数中，读入了图的信息；在 `print_graph` 函数中，输出了图的邻接表表示。