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#ifndef VECTOR_H
#define VECTOR_H
#include <iostream>
namespace VECTOR {
class vector
{
public:
enum Mode {RECT, POL};
private :
double x;
double y;
double mag;
double ang;
Mode mode;
void set_mag();
void set_ang();
void set_x();
void set_y();
public:
vector();
vector(double n1,double n2,Mode form = RECT);
void reset(double n1,double n2,Mode form = RECT);
~vector();
double xval() const {return x;}
double yavl() const {return y;}
double magval() const {return mag;}
double angval() const {return ang;}
void polar_mode();
void rect_mode();
vector operator+(const vector & b)const;
vector operator-(const vector & b)const;
vector operator-()const;
vector operator*(double n)const;
friend vector operator*(double n, vector & a);
friend std::ostream & operator<<(std::ostream &os, const vector & v);
};
}
#endif // VECTOR_H
#include "vector.h"
#include <cmath>
using std::cout;
using std::endl;
using std::sqrt;
using std::sin;
using std::cos;
using std::atan;
using std::atan2;
namespace VECTOR {
const double Rad_to_deg = 45.0 / atan(1.0);
//private methods
void vector::set_mag()
{
mag = sqrt(x * x + y * y);
}
void vector::set_ang()
{
if(x == 0.0 && y == 0.0)
ang = 0.0;
else
ang = atan2(y,x);
}
void vector::set_x()
{
x = mag * cos(ang);
}
void vector::set_y()
{
y = mag * sin(ang);
}
//pulice methods
vector::vector()
{
x = y = mag = ang = 0.0;
mode = RECT;
}
vector::vector(double n1, double n2, Mode form)
{
mode = form;
if(form = RECT)
{
x = n1;
y = n2;
set_mag();
set_ang();
}
else if(form = POL)
{
mag = n1;
ang = n2;
set_x();
set_y();
}
else
{
cout << "Incorrect 3rd argument to vector() --";
cout << "vector set to 0\n";
x = y = mag = ang = 0.0;
mode = RECT;
}
}
void vector::reset(double n1, double n2, Mode form)
{
mode = form;
if(form = RECT)
{
x = n1;
y = n2;
set_mag();
set_ang();
}
else if(form = POL)
{
mag = n1;
ang = n2;
set_x();
set_y();
}
else
{
cout << "Incorrect 3rd argument to vector() --";
cout << "vector set to 0\n";
x = y = mag = ang = 0.0;
mode = RECT;
}
}
vector::~vector()
{
//nothing to ~vector
}
void vector::polar_mode()
{
mode = POL;
}
void vector::rect_mode()
{
mode = RECT;
}
vector vector::operator+(const vector & b)const
{
return vector(x + b.x,y + b.y);
}
vector vector::operator-(const vector & b)const
{
return vector(x - b.x,y - b.y);
}
vector vector::operator-()const
{
return vector(-x,-y);
//构造函数,只送入X,Y,但是ANG,MAG也同时进行了设置,如果不使用此方式,必须将代码加上MAG,ANG的计算
}
vector vector::operator*(double n)const
{
return vector(n * x,n * y);
}
vector operator*(double n,const vector & v)
{
return v * n;
}
std::ostream & operator<<(std::ostream & os,const vector & v)
{
if(v.mode == vector::RECT)
os << "(x,y) = (" << v.x << ", " << v.y << ")";
else if(v.mode == vector::POL)
{
os << "(m,a) = (" << v.mag << ", " << v.ang * Rad_to_deg << ")";
}
else
os << "vector object mode is invalid!";
return os;
}
}
#include <iostream>
#include "vector.h"
#include <cstdlib>
#include <ctime>
int main()
{
using namespace std;
using VECTOR::vector;
srand((unsigned)time(0));
double direction;
vector step;
vector result(0.0,0.0);
unsigned long steps = 0;
double target;
double dstep;
cout << "Enter target distance (q to quit):";
while(cin >> target)
{
cout << "Enter step length:";
if(!(cin >> dstep))
break;
while(result.magval() < target)
{
direction = rand() % 360;
// cout << "the direction is " << direction << endl;
step.reset(dstep,direction,vector::POL);
result = result + step;
steps++;
cout << "the steps is " << steps << endl;
}
cout << "After " << steps << " steps, the subject "
"has the following lovation:\n";
cout << result << endl;
result.polar_mode();
cout << " or\n" << result << endl;
cout << "Average outward distance per step = "
<< result.magval()/steps << endl;
steps = 0;
result.reset(0.0,0.0);
cout << "Enter target distance (q to quit): ";
}
cout << "Bye\n";
cin.clear();
while(cin.get() != '\n')
continue;
return 0;
}