C++：实现数学向量Vector

c++ no
作者：陈小默

本节内容用来复习前两节知识点
定义向量的加减乘除操作和内积、外积。

vector.h

#ifndef primer_vector_h
#define primer_vector_h
class Vector{
private:
    double x,y;
    double length,angle;
    double PI=3.1415926535898;
public:
    Vector(double x,double y);
    Vector(double length,float angle);
    ~Vector();
    double getX(){return x;}
    double getY(){return y;}
    double getLength(){return length;}
    double getAngle(){return 180*(angle/PI);}
    //operator
    Vector operator+(Vector &v){
        double x_ = this->x;
        double y_ = this->y;
        x_+=v.getX();
        y_+=v.getY();
        return Vector(x_,y_);
    }
    Vector operator-(Vector &v){
        double x_ = this->x;
        double y_ = this->y;
        x_-=v.getX();
        y_-=v.getY();
        return Vector(x_,y_);
    }
    Vector operator-(){
        double x_ = 0.0-this->x;
        double y_ = 0.0-this->y;
        return Vector(x_,y_);
    }
    Vector operator*(double n){
        double x_ = n*this->x;
        double y_ = n*this->y;
        return Vector(x_,y_);
    }
    Vector operator/(double n){
        double x_ = this->x/n;
        double y_ = this->y/n;
        return Vector(x_,y_);
    }
    double operator>(Vector &v);//投影
    double operator>>(Vector &v);//点乘
    double operator*(Vector &v);//叉乘
    //friend
    friend Vector operator*(double n,Vector &v){
        return v * n;
    }
};
#endif

实现vector.cpp

#include"stdafx.h"
#include "vector.h"
#include<cmath>
Vector::Vector(double x,double y){
    Vector::x = x;
    Vector::y = y;
    Vector::length = std::sqrt(x*x+y*y);
    if(x==0&&y==0){
        Vector::angle = 0.0;
    }else {
        Vector::angle = std::atan2(y,x);
    }
}
Vector::Vector(double length,float angle){
    Vector::length = length;
    Vector::angle = angle*PI/180;
    Vector::x=((int(angle)-90)%180==0)?0:length*std::cos(Vector::angle);
    Vector::y=(int(angle)%180==0)?0:length*std::sin(Vector::angle);
}
Vector::~Vector(){}
double Vector::operator>(Vector &v){
    double l1 = this->length;
    double cos = std::cos(std::abs(v.angle-this->angle));
    return cos*l1;
}
double Vector::operator>>(Vector &v){
    double l2 = v.getLength();
    double s = (*this)>v;
    return s*l2;
}
double Vector::operator*(Vector &v){
    double l1 = this->length;
    double l2 = v.getLength();
    double sin = std::sin(std::abs(v.angle-this->angle));
    return l1*l2*sin;
}