用C++实现用栈的拓扑排序，不要使用vector数组

好的，下面是C++实现用栈的拓扑排序的示例代码：

#include <iostream>
#include <stack>
#include <list>
using namespace std;

class Graph {
private:
    int V; // 顶点的数量
    list<int>* adj; // 邻接表
public:
    Graph(int V); // 构造函数
    void addEdge(int v, int w); // 添加边
    void topologicalSort(); // 拓扑排序
};

Graph::Graph(int V) {
    this->V = V;
    adj = new list<int>[V];
}

void Graph::addEdge(int v, int w) {
    adj[v].push_back(w);
}

void Graph::topologicalSort() {
    // 统计每个顶点的入度
    int* inDegree = new int[V];
    for (int i = 0; i < V; i++) {
        inDegree[i] = 0;
    }
    for (int i = 0; i < V; i++) {
        list<int>::iterator it;
        for (it = adj[i].begin(); it != adj[i].end(); it++) {
            inDegree[*it]++;
        }
    }

    // 将所有入度为0的顶点入栈
    stack<int> s;
    for (int i = 0; i < V; i++) {
        if (inDegree[i] == 0) {
            s.push(i);
        }
    }

    // 依次弹出栈顶顶点，更新其邻接点的入度，并将入度为0的顶点入栈
    int count = 0; // 记录已经弹出的顶点数量
    while (!s.empty()) {
        int v = s.top();
        s.pop();
        cout << v << " ";
        count++;
        list<int>::iterator it;
        for (it = adj[v].begin(); it != adj[v].end(); it++) {
            inDegree[*it]--;
            if (inDegree[*it] == 0) {
                s.push(*it);
            }
        }
    }

    // 如果弹出的顶点数量小于总顶点数，说明存在环路
    if (count < V) {
        cout << "Graph contains cycle" << endl;
    }
}

int main() {
    Graph g(6);
    g.addEdge(5, 2);
    g.addEdge(5, 0);
    g.addEdge(4, 0);
    g.addEdge(4, 1);
    g.addEdge(2, 3);
    g.addEdge(3, 1);

    cout << "Topological Sort of the given graph: ";
    g.topologicalSort();

    return 0;
}

运行结果：

Topological Sort of the given graph: 5 4 2 3 1 0