Undefined reference to functions

[Jack816]

Could someone explain why every time I call a function in main, it says it is a undefined reference to it?

main.cpp

// A Sophisticated Rectangle Class
#include <iostream>
#include <stdexcept>
#include "Rectangle.hpp" // include definition of class Rectangle
/*

Create a sophisticated Rectangle class. This class stores only the Cartesian coordinates of the four corners of the
rectangle. The constructor calls a set function that accepts four sets of coordinates and verifies that
each of these is in the first quadrant with no single x- or y-coordinate larger than 20.0. The set function
also verifies that the supplied coordinates do, in fact, specify a rectangle.

Provide member functions that calculate the length, width, perimeter and area. The length is the larger of the two
dimensions.

Include a predicate function square that determines whether the rectangle is a square.
*/

int main() {
   Point w{1.0, 1.0};
   Point x{5.0, 1.0};
   Point y{5.0, 3.0};
   Point z{1.0, 3.0};
   Point j{0.0, 0.0};
   Point k{1.0, 0.0};
   Point m{1.0, 1.0};
   Point n{0.0, 1.0};

   Rectangle r1{z, y, x, w};
   std::cout << "Rectangle 1:\n";
   std::cout << "length = " << r1.length();
   std::cout << "\nwidth = " << r1.width();
   r1.perimeter();
   r1.area();
   std::cout << "\nThe rectangle "
      << (r1.square() ? "is" : "is not")
      << " a square.\n";

   Rectangle r2{j, k, m, n};
   std::cout << "\nRectangle 2:\n";
   std::cout << "length = " << r2.length();
   std::cout << "\nwidth = " << r2.width();
   r2.perimeter();
   r2.area();
   std::cout << "\nThe rectangle "
      << (r2.square() ? "is" : "is not")
      << " a square.\n";

}

Rectangle.hpp

#ifndef RECTANGLE_HPP_INCLUDED
#define RECTANGLE_HPP_INCLUDED
#include <math.h>
struct Point
{
    double x;
    double y;
};

class Rectangle
{
    private:
        double x1, y1, x2, y2, x3, y3, x4, y4;
        double rectLength;
        double rectWidth;
        double rectArea;
        double rectPerimeter;
    public:
        Rectangle(Point &cord1, Point &cord2, Point &cord3, Point &cord4)
        {
            x1 = cord1.x;
            y1 = cord1.y;
            x2 = cord2.x;
            y2 = cord2.y;
            x3 = cord3.x;
            y3 = cord3.y;
            x4 = cord4.x;
            y4 = cord4.y;
        }
        double length();
        double width();
        void area();
        void perimeter();
        bool square();

};

#endif // RECTANGLE_HPP_INCLUDED 

Rectangle.cpp

class Rectangle;
double Rectangle::length()
{
    rectLength = fabs(x1 - x2);
     return rectLength;
}

double Rectangle::width()
{
    rectWidth = fabs(y1 - y2);
    return rectWidth;
}

void Rectangle::area()
{
    rectArea = rectLength * rectWidth;
}

void Rectangle::perimeter()
{
    rectPerimiter = (2 * rectLength) + (2 * rectWidth);
}

bool Rectangle::square()
{
    if(rectLength == rectWidth)
    {
        return 1;
    }
    else
    {
        return 0;
    }
}

[cire]

Make sure that Rectangle.cpp is part of the project (or is specified separately on the command line along with the resulting object file when linking.)

[integralfx]

In Rectangle.hpp, #include <cmath> , which is the C++ header, and not #include <math.h> , which is the C header.

In Rectangle.cpp, you need to #include "Rectangle.hpp" and remove the class declaration of Rectangle.

[Jack816]

Thank you for all the suggestions. The main problem was that they were not all part of the same project. By adding them I was able to resolve my issue.