C++源文件和头文件关于求解直线方程和法线方程

#include <iostream> #include <math.h> #include <cmath> #include "linear_equation.h" using namespace std; #define INF 9999 //origin function A*x+B*y+C=0 linear_e::linear_e() { A = 0; B = 0; C = 0; degree = 0; radian = 0; k = 0; } linear_e::~linear_e() { cout << "linear_e is calling destructor!" << endl; } float linear_e::translation_rad_angle(int mode,float value) //input varialbes: // mode 0----translate radian to degree!! // 1----translate degree to radian! //statement: //when u need output angle(translate rad to degree), u need set mode=1, function will return degree. //when u need output radian(translate degree to radian), u need set mode=0,function will return radian. { if(mode == 1) //mode == 1 ,value is rad, and u wanna a degree. return value*180/M_PI; else if(mode == 0) //mode == 0,value is degree, and u wanna a rad. return value*M_PI/180; } void linear_e::linear_equation_two_point(float x1,float y1,float x2,float y2) //input variables: //(x1,y1),(x2,y2) is two points that we already know. //equation: (x-x1)/(x2-x1)=(y-y1)/(y2-y1)!!! //statement: //we utility two knowed points to solve linear equation! { float deta=0.0; if((x2-x1) == 0) //Vertical y-axis linear equation: x-x0=0 { A = 1; //linear_equation_two_point B = 0; C = -x2; k = INF; radian = M_PI/2; degree = 90; } else //linear equation: y=deta*x-deta*x1+y2 ----> -deta*x+y+deta*x1-y1=0 { deta = (y2-y1)/(x2-x1); A = -deta; B = 1; C = deta*x1-y1; k = deta; radian = atan(k); degree = translation_rad_angle(0,radian); } } void linear_e::linear_equation_intercept_xy(float xa, float xb) //input variables: // the intercept of xoy-axis, x-axis = xa, y-axis = ya //equation: x/a+y/b = 1 ----> b*x+a*y-a*b=0 { A = xb; B = xa; C = -xa*xb; k = -xb/xa; radian = atan(k); degree = translation_rad_angle(0,radian); } void linear_e::linear_equation_point_slpoe(float x0, float y0, float slope_k) //input varibles: //know point (x0,y0) and slope_k, to slove linear equation // slop_k must exist,cannot be "NULL". //equation: y-y0=slope_k*(x-x1) ----> -slope_k*x+y+slope_k*x0-y0=0 { A = -slope_k; B = 1; C = slope_k*x0-y0; k = slope_k; radian = atan(k); degree = translation_rad_angle(0,radian); } void linear_e::normal_equation(float x1, float y1, float slope_k) //input varibles: //slove point (x1,y1) normal equation, //origin equation slope is slope_k. //equation: y=K*x+b ----> y=-1/slope_k*x+b ----> (1/slope)*x+y-((1/slope_k)*x1+y1)=0 { if (slope_k == INF) //origin quation is verical x-axis, so normal equation is parallel x-axis. { A = 0; B = 1; C = -y1; k = 0; radian = 0; degree = 0; } else if (slope_k == 0) //origin equqtion is parallel x-axis, so normal equation is vertical x-axis. { A = 1; B = 0; C = -x1; k = INF; radian = M_PI/2; degree = 90; } else { A = (-1)/(-slope_k); B = 1; C = -((1/slope_k)*x1+y1); k = -1/slope_k; radian = atan(k); degree = translation_rad_angle(0,radian); } } void linear_e::display() { cout << "A = " << A << ",B = " << B << ",C = " << C << ",equation is:" << A << "*x+" << B << "*y+" << C <<" =0" <<'\n'; cout << "angle = "<< degree << ",radian" << radian << ",k = " << k << endl; cout << "===========================================================" <<endl; }