怎么求两点距离？

Question

C++问题！！！！！
100[ 标签：c++ ] 类L，其中有用一个只有一个参数的普通成员函数。怎么求两点距离？？

class Location
{
public:
Location(double,double);//构造
double Getx();
double Gety();//最后用于返回坐标
double distance(Location &);//就是这个
friend double distance(Location &,Location &);//用友元函数求距离
private:
double x,y;//坐标
};

Answer 1

#include<iostream>#include<math.h>class Location{public:Location(double xx,double yy):x(xx),y(yy){}//构造double Getx(){return x;}double Gety(){return y;}//最后用于返回坐标double distance(Location & locationItem);//就是这个friend double distance(Location &,Location &);//用友元函数求距离private:double x,y;//坐标};double Location::distance(Location & locationItem){double l;l=sqrt(pow(x-locationItem.Getx(),2)+pow(y-locationItem.Gety(),2));return l;}double distance(Location &locationItem1,Location &locationItem2){//这个函数是友元的，可以下面两种方法。double l;// l=sqrt(pow(locationItem1.Getx()-locationItem2.Getx(),2)+pow(locationItem1.Gety()-locationItem2.Gety(),2));l=sqrt(pow(locationItem1.x-locationItem2.x,2)+pow(locationItem1.y-locationItem2.y,2));return l;}int main(){Location locationItem1(8,9);Location locationItem2(5,5);double result;result=distance(locationItem1,locationItem2);std::cout<<result<<std::endl;result=locationItem1.distance(locationItem2);std::cout<<result<<std::endl;result=locationItem2.distance(locationItem1);std::cout<<result<<std::endl;return 0;}这很明白了。应该没问题了吧？你建个工程，直接复制我的代码，而且还是按你的改的。能运行。然后自己再看。

Answer 2

给你写了个函数,你试试看,需要包含math.h全局函数版本double distance(Location const& a, Location const& b){double dx = a.GetX() - b.GetX();double dy = a.GetY() - b.GetY();return sqrt(dx * dx + dy * dy);}成员变量版本double Location::distance(Location const& b) const{double dx = GetX() - b.GetX();double dy = GetY() - b.GetY();return sqrt(dx * dx + dy * dy);}

Answer 3

#include <iostream>#include <math.h>using namespace std;class Location{public:Location(double,double);//构造double Getx();double Gety();//最后用于返回坐标double distance(Location &);//就是这个friend double distance(Location &,Location &);//用友元函数求距离private:double x,y;//坐标};Location::Location(double x1,double y1){x=x1;y=y1;}double Location:: distance(Location &p){double dx=x-p.Getx();double dy=x-p.Gety();double d=0;d=sqrt( pow(dx,2)+ pow(dy,2 ) );return d;}double Location:: Getx(){return x;}double Location:: Gety(){return y;}double distance(Location &p1,Location &p2){double d=sqrt( pow((p1.Getx()-p2.Getx()),2)+pow((p2.Gety()-p2.Gety()),2) );return d;}int main(){Location p1(3,5);Location p2(10,20);double dist=0.0;dist=p2.distance(p1);cout << "p1("<<p1.Getx()<<","<<p1.Gety()<<") and p2("<<p2.Getx()<<","<<p2.Gety()<<") distance is :" << dist <<endl; getchar();return 0;}运行结果：p1(3,5) and p2(10,20) distance is :8.60233