C++实现离散数学的关系类，支持传递闭包运算

　　
　　Graph底层是一个int型二维数组，当进行addEdge操作时，相当于在关系图的相应位置打上记号。  
  
  
  1 #include <vector>
#include <cassert>
#include <iostream>
using namespace std;
class Graph{
private:
    int n;
    int** graph;
public:
    Graph(int n){
        this->n = n;
        graph = new int*[n];
        for(int i=0;i<n;i++)
            graph[i] = new int[n];
        for(int i=0;i<n;i++)
            for(int j=0;j<n;j++)
                graph[i][j] = 0;
    }
    void addEdge(int a,int b){
        assert(a>0&&a<=n);
        assert(b>0&&b<=n);
        if(connected(a-1,b-1))
            return;
        graph[a-1][b-1] = 1;
    }
    void removeEdge(int a,int b){
        assert(a>0&&a<=n);
        assert(b>0&&b<=n);
        if(!connected(a,b))
            return;
        graph[a-1][b-1] = 0;
    }
    bool connected(int a,int b){
        return graph[a][b]==1;
    }
    void plus(int a1,int b1,int a2,int b2){
        if(graph[a1][b1]==0)
            graph[a1][b1]+=graph[a2][b2];
        else
            return;
    }
    void display(){
        cout<<"Matrix Form:"<<endl;
        for(int i=0;i<n;i++){
            for(int j = 0;j<n;j++)
                cout<<graph[i][j]<<" ";
            cout<<endl;
        }
        cout<<"Front: ";
        for(int i=0;i<n;i++)
            for(int j=0;j<n;j++){
                if(graph[i][j])
                    cout<<"<"<<i+1<<","<<j+1<<">  ";
        }
        cout<<endl;
    }
};

// RelationShip关系类与Graph类建立起has-a的关系

class RelationShip{
private:
    bool print;
    int num_points;
    Graph graph;
public:
    RelationShip(int num):graph(num){
        print = true;
        this->num_points = num;
    }

    void add_RS(int a,int b){
        graph.addEdge(a,b);
    }

    void remove_RS(int a,int b){
        graph.removeEdge(a,b);
    }

    void transfer(){ //将矩阵作传递化闭包运算
        for(int i = 0;i<num_points;i++){
            for(int j = 0;j<num_points;j++){
                if(graph.connected(j,i)){
                    for(int k = 0;k<num_points;k++)
                        graph.plus(j,k,i,k);
                }
            }
        }
        print = true;
    }

    void show(){
        graph.display();
    }
};

int main(){
    cout<<"请输入你希望的元素个数:"<<endl;
    int n;
    while(cin>>n){
        RelationShip op = RelationShip(n);
        int num;
        cout<<"你想联系起多少对关系呢？"<<endl;
        cin>>num;
        while(num--){
            cout<<"请输入[1,"<<n<<"]之间的任意一对序偶"<<endl;
            int a,b;
            cin>>a>>b;
            op.add_RS(a,b);
        }
        cout<<"你想进行传递闭包运算吗？(yes or no)"<<endl;
        string s;
        cin>>s;
        if(s=="yes")
            op.transfer();
        op.show();
    }
}

 基础数据结构是邻接矩阵