I'm still learning classes in C++ and I don't understand this error that I'm getting from `#include QuadraticEquation`. Here's my code:

#include <iostream>

#include <cmath>

#include "QuadraticEquation"

using namespace std;

class QuadraticEquation{

private:

double a = 0, b = 0, c = 0;

public:

QuadraticEquation(double a, double b, double c)

{

this-> a = a;

this-> b = b;

this-> c = c;

}

double getA(){

return a;

}

double getB(){

return b;

}

double getC(){

return c;

}

double getDiscriminant(){

return (pow(b, 2) - 4 * a * c);

}

double getRoot1(){

return ((-b + sqrt(pow(b, 2) - 4 * a * c)) / (2 * a));

}

double getRoot2(){

return ((-b - sqrt(pow(b, 2) - 4 * a * c)) / (2 * a));

}

};

int main()

{

double a = 0, b = 0, c = 0;

//User enters values for a, b, and c.

cout << "Enter the values for a, b, and c: ";

cin >> a >> b >> c;

//Object created.

QuadraticEquation q1 (a, b, c);

if (q1.getDiscriminant() > 0){

cout << "Root 1: " << q1.getRoot1() << ", Root 2: " << q1.getRoot2() << endl;

//Two Roots

}else if (q1.getDiscriminant() == 0){

//One root

cout << "Root 1: " << q1.getRoot1() << endl;

}else{

//No roots

cout << "The equation has no real roots." << endl;

}

}