Ошибка LNK2019 unresolved external symbol _main referenced in function

#include <iostream>
#include "Rectangle.hpp"
 
Rectangle::Rectangle(float rectangle_width, float rectangle_height)
{
    getArea(rectangle_width, rectangle_height);
}
 
void Rectangle::getArea(float rectangle_width, float rectangle_height)
{
    width = rectangle_width;
    height = rectangle_height;
    float area;
    area = width*height;
    std::cout << "Rectangle Area:", area;
    std::cout << "\n";
}
void Rectangle::getFrameRect()
{
    width = width + 10;
    height = height + 10;
    std::cout << "Frame Rectangle Properties:";
    std::cout << "\n";
    std::cout << "Width:", width;
    std::cout << "\n";
    std::cout << "Height", height;
    std::cout << "\n";
    
}
void Rectangle::move(point_t posmove)
{
 
    std::cout << "Rectangle coordinates:", pos.x,pos.y;
    pos = posmove;
    std::cout << "Now:", pos.x, pos.y;
 
}

#ifndef RECTANGLE_HPP
#define RECTANGLE_HPP
 
#include "Shape.hpp"
#include "base-types.hpp"
 
class Rectangle:public Shape
{
private:
    float rarea;
    float width;
    float height;
    rectangle_t framerect;
    point_t pos;
 
public:
    Rectangle(float, float);
    
    virtual void getArea(float, float);
    virtual void getFrameRect();
    virtual void move(point_t);
};
#endif RECTANGLE_HPP

#include <iostream>
#include "rectangle.hpp"
 
int main () {
    Rectangle r(10, 10);
    r.getFrameRect();
}