#ifndef DIEDGE_H_INCLUDED

#define DIEDGE_H_INCLUDED

#include "func.h"

/*

区别于无向边,v->w == v,w具有固定的含义

API from v to w

*/

class DiEdge{

private:

int v;

int w;

double weight;

public:

DiEdge()

:v(0),w(0),weight(0.0){}

DiEdge(int v,int w,double weight)

:v(v),w(w),weight(weight){}

int from()const { return v;}

int to()const {return w;}

double getWeight()const {return weight;} //const成员函数 不改变类对象的内部数据

friend bool operator<(const DiEdge& a,const DiEdge& b);

friend bool operator>(const DiEdge& a,const DiEdge& b);

friend bool operator==(const DiEdge& a,const DiEdge& b);

friend bool operator!=(const DiEdge& a,const DiEdge& b);

};

bool operator<(const DiEdge& a,const DiEdge& b){

return a.getWeight() < b.getWeight();

}

bool operator>(const DiEdge& a,const DiEdge& b){

return a.getWeight() > b.getWeight();

}

bool operator==(const DiEdge& a,const DiEdge& b){

return a.getWeight()==b.getWeight() && a.from()==b.from() && a.to()==b.to();

}

bool operator!=(const DiEdge& a,const DiEdge& b){

return a.getWeight()!=b.getWeight() || a.from()!=b.from() || a.to()!=b.to();

}

#endif // DIEDGE_H_INCLUDED