C++Primer Plus第十一章类的使用，课后练习3，还是醉汉回家的故事 3，最慢和最快及平均概率的问题-优快云博客

修改程序清单 11.15，使之报告N次测试中的最高、最低和平均步数(其中N是用户输入的整数)
而不是报告每次测试的结果。

头文件和实现文件不变，这里为大家方便还是贴上代码

//vect.h -- Vector class with <<,mode state
#if 1
#ifndef	VECTOR_H_	
#define VECTOR_H_
#include<iostream>
namespace VECTOR
{
	class Vector
	{
	public:
		enum Mode { RECT, POL };//以此为直角坐标，极坐标（长度，角度）
		//RECT for rectangular,POL for Polar modes
	private:
		double x;//horizontal value x方向x坐标
		double y;//vertical value  y方向y坐标
		double mag; //length of value  极坐标的长度
		double ang;//direction of vector in degrees，极坐标的角度
		Mode mode;//RECT or POL
		//private methods for setting values
		void set_mag();
		void set_ang();
		void set_x();
		void set_y();
	public:
		Vector();
		Vector(double x, double y, Mode form = RECT);
		void reset(double x, double y, Mode form = RECT);
		~Vector();
		double xval()const { return x; }//report x val
		double yval()const { return y; }//report y val
  		double magVal()const { return mag; }//report magnitude
		double angval()const { return ang; }//report angle
		void polar_mode();//set mode to POL
		void rect_mode();//set mode to RECT
		//operator overloading 
		Vector operator+(const Vector& b)const;
		Vector operator-(const Vector& b)const;
		Vector operator-()const;
		Vector operator*(double n)const;
		//friends
		friend Vector operator*(double n, const Vector& a);
		friend std::ostream& operator<<(std::ostream& os, const Vector& v);
	};// end Vector
}//end namespace VECTOR
#endif

文件不变，不过之前的函数Vector(double,double,mode)有一个bug,更新过来了。
大家有机会去研究一下。

#if 1
#include<cmath>	
#include"vector.h" //includes<iostream>
using std::sqrt;
using std::sin;
using std::cos;
using std::atan;
using std::atan2;
using std::cout;
using std::endl;
namespace VECTOR
{
	//comput degrees in one radian 
	const double Rad_to_deg = 45.0 / atan(1.0);
	//should be about 57.2957795130823

	//private methods
	//calculates magnitude from x and y 
	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);
		}
	}
	//set x from polar coorinate 
	void Vector::set_x()
	{
		x = mag * cos(ang);
	}
	//set y from polar coorinate
	void Vector::set_y()
	{
		y = mag * sin(ang);
	}
	//public methods 
	//default constructor
	Vector::Vector()
	{
		y = x = mag = ang = 0.0;
		mode = RECT;
	}

	//construct vector from rectangular coordinates if form is r 
	//(the default) or else from polay coordinates if form is p
	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 / Rad_to_deg;
			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;
		}
	}
	//reset vector from rectangular coorinates if form is 
	//RECT(the default) or else from polar coorinates if 
	//form is POL
	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 / Rad_to_deg;
			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()//destructor
	{

	}

	void Vector::polar_mode()//set to polay mode 
	{
		mode = POL;
	}

	void Vector::rect_mode() // set to rectangular mode
	{
		mode = RECT;
	}

	//operator overloading 
	//add two Vectors 
	Vector Vector::operator+(const Vector& b)const
	{
		return Vector(x + b.x, y + b.y);
	}
	//sub vector b from a 
	Vector Vector::operator-(const Vector& b)const
	{
		return Vector(x - b.x, y - b.y);
	}

	//reverse sign of Vector
	Vector Vector::operator-()const
	{
		return Vector(-x, -y);
	}

	//multyply vector by n 
	Vector Vector::operator*(double n)const
	{
		return Vector(n * x, n * y);
	}

	//friend methods
	//multiply n by Vector a 
	Vector operator*(double n, const Vector& a)
	{
		return a * n;
	}

	//display rectangular coorinates if mode is RECT
	//else display polar coordinates if mode is POL
	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;
	}
}//end namespace VECTOR

#endif // 0

测试函数，有条件的兄弟们可以测试一下
这里每次执行结果都是不一样的。随机的

#pragma 练习3 3.cpp
/*
*/
#if 1
#include <iostream>
#include"vector.h"
using namespace std;
using namespace VECTOR;
int main()
{
	srand(time(0));
	while (true)
	{
		double setp;
		double distance;
		unsigned times;
		unsigned max_setps = 0;
		unsigned min_setps = numeric_limits<unsigned>::max();
		unsigned sum_setps = 0;
		cout << "请输入距离：";
		cin >> distance;
		if (!cin || distance <= 0)break;

		//清空缓冲区
		cin.clear();
		cin.ignore(numeric_limits<streamsize>::max(), '\n');

		cout << "请输入步长：";
		cin >> setp;
		if (!cin || setp <= 0)break;
		
		//清空缓冲区
		cin.clear();
		cin.ignore(numeric_limits<streamsize>::max(), '\n');

	

		cout << "请输入测试循环次数：";
		cin >> times;
		if (!cin)break;

		//清空缓冲区
		cin.clear();
		cin.ignore(numeric_limits<streamsize>::max(), '\n');

		cout.setf(ios_base::fixed, ios_base::floatfield);
		cout.precision(2);
		for (unsigned i = 0; i < times; i++)
		{
			unsigned  cntSteps = 0;
			Vector vec(0,0,Vector::POL);
			cout << i << ": ";

			while(vec.magVal() < distance)
			{
				vec = vec + Vector(setp, rand() % 360, Vector::POL);
				cntSteps++;
			//	cout << cntSteps << endl;
			}
			cout << cntSteps << "步行到" << vec << endl;
		   
			if (cntSteps > max_setps)
			{
				max_setps = cntSteps;
			}
			if (cntSteps < min_setps)
			{
				min_setps = cntSteps;
			}
			sum_setps += cntSteps;
		}
		cout << "距离" << distance << ",步长" << setp << ",测试" << times << "次，最多次步"
			<< max_setps << "步，最少走步" << min_setps << "步，平均走步" << sum_setps / times << "步\n";
	}
	cin.clear();
	return 0;
}
#endif 
#pragma endregion