Least Square Method for fitting a straight line c ++ Program

// Point. h
Class Point // Point class declaration
{
Public: // external interface
Point (float xx = 0, float YY = 0) {x = xx; y = YY ;}
Float getx () {return X ;}
Float Gety () {return y ;}
Friend float linefit (point l_point [], int n_point); // youyuan Function
// Int type variable is the number of points
PRIVATE: // Private Data Member
Float X, Y;
};
// End of point. h

// Main. cpp
# Include <iostream>
# Include <cmath>
# Include "point. H"
Using namespace STD;
Float linefit (point l_point [], int n_point) // youyuan function body
{
Float av_x, av_y; // declare the variable
Float l_xx, l_yy, l_xy;
// Variable Initialization
Av_x = 0; // The average value of X
Av_y = 0; // The average value of Y
L_xx = 0; // LXX
Rochelle YY = 0; // lyy
Rochelle xy = 0; // lxy
For (INT I = 0; I <n_point; I ++) // calculate the average values of X and Y
{
Av_x + = l_point [I]. X/n_point;
Av_y + = l_point [I]. Y/n_point;
}
For (I = 0; I <n_point; I ++) // calculate LXX, lyy, and lxy
{
Rochelle xx + = (Rochelle point [I]. X-av_x) * (Rochelle point [I]. X-av_x );
Rochelle YY + = (Rochelle point [I]. Y-av_y) * (Rochelle point [I]. Y-av_y );
Roxy + = (Rochelle point [I]. X-av_x) * (Rochelle point [I]. Y-av_y );
}
Cout <"this line can be fitted by Y = ax + B." <Endl;
Cout <"A =" <l_xy/l_xx; // output regression coefficient
Cout <"B =" <av_y-L_xy * av_x/l_xx <Endl; // output regression coefficient B
Return float (l_xy/SQRT (l_xx * l_yy); // return the correlation coefficient R
}

Int main ()
{
Point l_p [10] = {point (6, 10), point (14,20), point (26, 30 ),
Point ),
Point (100,100), Point (), Point ()}; // initialize the data Point
Float r = linefit (l_p, 10); // linear regression calculation
Cout <"Line coefficient r =" <r <endl; // output Correlation coefficient
}