问题描述
代码：
include 'stdafx.h'#include<iostream>#include<string>#include<cmath>#include<sstream>using namespace std;#define PI 3.141592653class VecPosition{public: VecPosition(double vx = 0,double vy = 0); VecPositionoperator -- (); VecPositionoperator + (const double &d); VecPositionoperator + (const VecPosition &p); VecPositionoperator - (const double &d); VecPositionoperator - (const VecPosition &p); VecPositionoperator * (const double &d); VecPositionoperator * (const VecPosition &p); VecPositionoperator / (const double &d); VecPositionoperator / (const VecPosition &p); void operator = (const double &d); void operator += (const VecPosition &p); void operator += (const double &d); void operator -= (const VecPosition &p); void operator -= (const double &d); void operator *= (const VecPosition &p); void operator *= (const double &d); void operator /= (const VecPosition &p); void operator /= (const double &d); bool operator != (const VecPosition &p); bool operator != (const double &d); bool operator == (const VecPosition &p); bool operator == (const double &d); void draw(); // 绘制到屏幕 string str(double dX, double dY);// 将向量坐标转为字符串，格式为“(x=, y=)”bool setX(double dX) {return false; } double getX() const {return m_x; } bool setY(double dY) {return false; } double getY() const {return m_y; }void setVecPosition(double dX=0 ,double dY=0 ); double getDistanceTo(const VecPosition p) {return sqrt((p.m_x-p.m_x)*(p.m_x-p.m_x) + (p.m_y-p.m_y)*(p.m_y - p.m_y)); }//获得两点间的距离 VecPosition setMagnitude(double d) {m_x = d*cos(this->getDirection());m_y = d*sin(this->getDirection());return *this; }//设置向量长度为d double getMagnitude(double d) const {return sqrt((m_x)*(m_x) + (m_y)*(m_y)); }//获取向量长度 double getDirection() const {double a[4] = { 0, 0, 1, 0 };double b[4] = {0,0,m_x,m_y };double t;double angle;t = ((a[0] - a[2])*(b[0] - b[2]) + (a[1] - a[3])*(b[1] - b[3])) / (sqrt(pow(a[0] - a[2], 2) + pow(a[1] - a[3], 2))*sqrt(pow(b[0] - b[2], 2) + pow(b[1] - b[3], 2)));cout << '这两个向量的夹角为:' << acos(t)*(180 / PI) << '度' << endl;return angle= acos(t)*(180 / PI); }//获取向量方向（与X轴夹角）bool isBetweenX(const VecPosition &p1, const VecPosition &p2) {return false; } bool isBetweenX(const double &d1, const double &d2) {return false; } bool isBetweenY(const VecPosition &p1, const VecPosition &p2) {return false; } bool isBetweenY(const double &d1, const double &d2) {return false; } // 判断坐标是否在给定两点的X，Y之间VecPosition normalize() {return VecPosition(cos(this->getDirection()), sin(this->getDirection())); }// 正规化坐标VecPosition rotate(double angle){ angle = angle / 180 * PI; //由于输进去的角度值不是幅度制，统一化成幅度值 angle += this->getDirection(); return VecPosition(this->getMagnitude(m_x)*cos(angle), this->getMagnitude(m_y)*sin(angle));}// 向量旋转static VecPosition getVecPositionFromPolar(double dMag, double ang) {ang = ang / 180 * PI; return VecPosition(dMag*cos(ang), dMag*sin(ang)); }// 根据极坐标获取笛卡尔坐标static double normalizeAngle(double angle) {angle = angle / PI * 180;//化成幅度值int a = int(angle / 180);if (a % 2 == 0) return angle - a * 180;else return angle - (a + 1) * 180; }// 将任意角度转为（－180，180]范围private: double m_x; double m_y; string a;};VecPosition::string str(double dX, double dY) { ostringstream stream; cout << '(x=' << dX << ', y=' << dY << ')'; return stream.str();}
问题解答
回答1：把VecPosition::string str(double dX, double dY) 写成 string VecPosition:: str(double dX, double dY) 试试
回答2：同意楼上。str才是VecPosition的成员函数。
