C++ igraph教程：从数据文件构建图并设置边权重和节点名称

#include <igraph/igraph.h>
#include <iostream>
#include <fstream>
#include <sstream>
#include <unordered_map>
#include <vector>

int main() {
    // 打开数据文件
    std::ifstream file('matrix.txt');
    std::string line;

    // 初始化数据结构
    std::vector<int> edges;
    std::vector<double> weights;
    std::vector<std::string> node_names;

    std::unordered_map<std::string, int> node_map;
    int node_count = 0;

    // 读取数据文件并构建图
    while (std::getline(file, line)) {
        std::istringstream iss(line);
        std::string u, v;
        double w;

        // 解析每一行数据
        if (!(iss >> u >> v >> w)) {
            break;  // 如果解析出错，跳出循环
        }

        // 处理源节点
        if (node_map.find(u) == node_map.end()) {
            // 如果节点不存在，将其添加到映射表和节点名称列表中
            node_map[u] = node_count;
            node_names.push_back(u);
            node_count++;
        }

        // 处理目标节点
        if (node_map.find(v) == node_map.end()) {
            // 如果节点不存在，将其添加到映射表和节点名称列表中
            node_map[v] = node_count;
            node_names.push_back(v);
            node_count++;
        }

        // 添加边和权重
        edges.push_back(node_map[u]);
        edges.push_back(node_map[v]);
        weights.push_back(w);
    }

    // 创建 igraph 图对象
    igraph_t graph;
    igraph_empty(&graph, node_count, IGRAPH_UNDIRECTED);

    // 添加边到图中
    igraph_vector_int_t edge_vector;
    igraph_vector_int_init(&edge_vector, edges.size());
    for (auto &edge : edges) {
        igraph_vector_int_push_back(&edge_vector, edge);
    }
    igraph_add_edges(&graph, &edge_vector, 0);
    igraph_vector_int_destroy(&edge_vector);

    // 设置边权重
    igraph_vector_t weights_vector;
    igraph_vector_init(&weights_vector, weights.size());
    for (auto &weight : weights) {
        igraph_vector_push_back(&weights_vector, weight);
    }
    igraph_cattribute_VAN_set(&graph, 'weight', 0, &weights_vector);
    igraph_vector_destroy(&weights_vector);

    // 设置节点名称
    igraph_strvector_t names_vector;
    igraph_strvector_init(&names_vector, node_names.size());
    for (auto &name : node_names) {
        igraph_strvector_add(&names_vector, name.c_str());
    }
    igraph_cattribute_VAS_setv(&graph, 'name', &names_vector);
    igraph_strvector_destroy(&names_vector);

    // 将图保存为GraphML文件
    FILE *outfile = fopen('gg.graphml', 'w');
    igraph_write_graph_graphml(&graph, outfile, IGRAPH_ALL);
    fclose(outfile);

    // 销毁图对象
    igraph_destroy(&graph);

    return 0;
}