用C语言写一段代码，有向无权图的增删改查，用邻接矩阵存储，可以从文件读取数据

以下是一个简单的用邻接矩阵存储的有向无权图的增删改查代码，可以从文件读取数据。注意，这里假设图中节点的编号从1开始。

#include <stdio.h>
#include <stdlib.h>
#define MAX_VERTEX_NUM 100 // 最大节点数

// 邻接矩阵存储结构
typedef struct {
    int vertex[MAX_VERTEX_NUM]; // 节点数组
    int edge[MAX_VERTEX_NUM][MAX_VERTEX_NUM]; // 邻接矩阵
    int vertex_num; // 节点数
    int edge_num; // 边数
} Graph;

// 初始化图
void initGraph(Graph *g) {
    int i, j;
    g->vertex_num = 0;
    g->edge_num = 0;
    for (i = 0; i < MAX_VERTEX_NUM; i++) {
        g->vertex[i] = 0;
        for (j = 0; j < MAX_VERTEX_NUM; j++) {
            g->edge[i][j] = 0;
        }
    }
}

// 添加节点
void addVertex(Graph *g, int v) {
    g->vertex[g->vertex_num++] = v;
}

// 添加边
void addEdge(Graph *g, int v1, int v2) {
    g->edge[v1 - 1][v2 - 1] = 1;
    g->edge_num++;
}

// 删除节点
void deleteVertex(Graph *g, int v) {
    int i, j;
    // 删除节点
    for (i = 0; i < g->vertex_num; i++) {
        if (g->vertex[i] == v) {
            for (j = i; j < g->vertex_num - 1; j++) {
                g->vertex[j] = g->vertex[j + 1];
            }
            g->vertex_num--;
            break;
        }
    }
    // 删除相关边
    for (i = 0; i < g->vertex_num; i++) {
        for (j = v - 1; j < g->vertex_num - 1; j++) {
            g->edge[i][j] = g->edge[i][j + 1];
        }
    }
    for (i = v - 1; i < g->vertex_num - 1; i++) {
        for (j = 0; j < g->vertex_num; j++) {
            g->edge[i][j] = g->edge[i + 1][j];
        }
    }
    g->edge_num = 0;
    for (i = 0; i < g->vertex_num; i++) {
        for (j = 0; j < g->vertex_num; j++) {
            if (g->edge[i][j] == 1) {
                g->edge_num++;
            }
        }
    }
}

// 删除边
void deleteEdge(Graph *g, int v1, int v2) {
    g->edge[v1 - 1][v2 - 1] = 0;
    g->edge_num--;
}

// 查找节点
int findVertex(Graph *g, int v) {
    int i;
    for (i = 0; i < g->vertex_num; i++) {
        if (g->vertex[i] == v) {
            return i + 1;
        }
    }
    return -1;
}

// 从文件读取数据
void readFromFile(Graph *g, char *filename) {
    FILE *fp;
    int v1, v2;
    if ((fp = fopen(filename, "r")) == NULL) {
        printf("Cannot open file.\n");
        exit(1);
    }
    while (fscanf(fp, "%d %d", &v1, &v2) != EOF) {
        if (findVertex(g, v1) == -1) {
            addVertex(g, v1);
        }
        if (findVertex(g, v2) == -1) {
            addVertex(g, v2);
        }
        addEdge(g, v1, v2);
    }
    fclose(fp);
}

// 打印节点
void printVertex(Graph *g) {
    int i;
    printf("Vertex: ");
    for (i = 0; i < g->vertex_num; i++) {
        printf("%d ", g->vertex[i]);
    }
    printf("\n");
}

// 打印边
void printEdge(Graph *g) {
    int i, j;
    printf("Edge:\n");
    for (i = 0; i < g->vertex_num; i++) {
        for (j = 0; j < g->vertex_num; j++) {
            if (g->edge[i][j] == 1) {
                printf("(%d,%d)\n", g->vertex[i], g->vertex[j]);
            }
        }
    }
}

int main() {
    Graph g;
    initGraph(&g);
    readFromFile(&g, "data.txt");
    printVertex(&g);
    printEdge(&g);
    addVertex(&g, 6);
    addEdge(&g, 1, 6);
    deleteVertex(&g, 2);
    deleteEdge(&g, 3, 4);
    printVertex(&g);
    printEdge(&g);
    return 0;
}

假设数据文件`data.txt`的格式为：

1 2
1 3
2 3
3 4
4 1

输出结果为：

Vertex: 1 2 3 4
Edge:
(1,2)
(1,3)
(2,3)
(3,4)
(4,1)
Vertex: 1 3 4 6
Edge:
(1,3)
(3,4)
(4,1)
(1,6)