Cannot compile Stroustrup GUI Libraries - c++

Question

I managed to install FLTK properly and it compiles if I use library like this #include<FL/Fl_Window.H>, but now I want to compile this libraries attached below through the code provided below also;
libraries link:
https://github.com/BjarneStroustrup/Programming-_Principles_and_Practice_Using_Cpp
here are also images, shown with the errors when compiling if I will uncomment Polygon it shows different error with this content Polygon is ambiguous provided screens below also;
CODE:
#include "Simple_window.h" // get access to our window library
#include "Graph.h" // get access to our graphics library facilities
int main()
{
using namespace Graph_lib; // our graphics facilities are in Graph_lib
Point tl {100,100}; // to become top left corner of window
Simple_window win {tl,600,400,"Canvas"}; // make a simple window
Polygon poly; // make a shape (a polygon)
poly.add(Point{300,200}); // add a point
poly.add(Point{350,100}); // add another point
poly.add(Point{400,200}); // add a third point
poly.set_color(Color::red); // adjust properties of poly
win.attach (poly); // connect poly to the window
win.wait_for_button(); // give control to the display engine
}
Error When compile code above:
C:\Users\ASUS\Desktop\C++\GUI_Train\Libs\Test_output.cpp: In function 'int main()':
C:\Users\ASUS\Desktop\C++\GUI_Train\Libs\Test_output.cpp:8:5: error: reference to 'Polygon' is ambiguous
8 | Polygon poly; // make a shape (a polygon)
| ^~~~~~~
In file included from C:\Users\ASUS\Desktop\C++\GUI_Train\Libs\GUI.h:11,
from C:\Users\ASUS\Desktop\C++\GUI_Train\Libs\Simple_window.h:2,
from C:\Users\ASUS\Desktop\C++\GUI_Train\Libs\Test_output.cpp:1:
C:\Users\ASUS\Desktop\C++\GUI_Train\Libs\Graph.h:248:8: note: candidates are: 'struct Graph_lib::Polygon'
248 | struct Polygon : Closed_polyline { // closed sequence of non-intersecting lines
| ^~~~~~~
In file included from C:/msys64/mingw64/include/windows.h:71,
from C:/msys64/mingw64/include/FL/Fl_Window.H:26,
from C:\Users\ASUS\Desktop\C++\GUI_Train\Libs\Window.h:5,
from C:\Users\ASUS\Desktop\C++\GUI_Train\Libs\GUI.h:10:
C:/msys64/mingw64/include/wingdi.h:3467:28: note: 'WINBOOL Polygon(HDC, const POINT*, int)'
3467 | WINGDIAPI WINBOOL WINAPI Polygon(HDC hdc,CONST POINT *apt,int cpt);
| ^~~~~~~
C:\Users\ASUS\Desktop\C++\GUI_Train\Libs\Test_output.cpp:9:5: error: 'poly' was not declared in this scope
9 | poly.add(Point{300,200}); // add a point
When Comment Out the using namespace Graph_lib
C:\msys64\mingw64\bin\g++.exe -fdiagnostics-color=always -g C:\Users\ASUS\Desktop\C++\GUI_Train\Libs\Test_output.cpp -lfltk -o C:\Users\ASUS\Desktop\C++\GUI_Train\Libs\Test_output.exe
C:\Users\ASUS\Desktop\C++\GUI_Train\Libs\Test_output.cpp: In function 'int main()':
C:\Users\ASUS\Desktop\C++\GUI_Train\Libs\Test_output.cpp:8:5: error: reference to 'Polygon' is ambiguous
8 | Polygon poly; // make a shape (a polygon)
| ^~~~~~~
In file included from C:\Users\ASUS\Desktop\C++\GUI_Train\Libs\GUI.h:11,
from C:\Users\ASUS\Desktop\C++\GUI_Train\Libs\Simple_window.h:2,
from C:\Users\ASUS\Desktop\C++\GUI_Train\Libs\Test_output.cpp:1:
C:\Users\ASUS\Desktop\C++\GUI_Train\Libs\Graph.h:248:8: note: candidates are: 'struct Graph_lib::Polygon'
248 | struct Polygon : Closed_polyline { // closed sequence of non-intersecting lines
| ^~~~~~~
In file included from C:/msys64/mingw64/include/windows.h:71,
from C:/msys64/mingw64/include/FL/Fl_Window.H:26,
from C:\Users\ASUS\Desktop\C++\GUI_Train\Libs\Window.h:5,
from C:\Users\ASUS\Desktop\C++\GUI_Train\Libs\GUI.h:10:
C:/msys64/mingw64/include/wingdi.h:3467:28: note: 'WINBOOL Polygon(HDC, const POINT*, int)'
3467 | WINGDIAPI WINBOOL WINAPI Polygon(HDC hdc,CONST POINT *apt,int cpt);
| ^~~~~~~
C:\Users\ASUS\Desktop\C++\GUI_Train\Libs\Test_output.cpp:9:5: error: 'poly' was not declared in this scope
9 | poly.add(Point{300,200}); // add a point
Error When Polygon is commented just to compile code without polygon:
C:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/12.2.0/../../../../x86_64-w64-mingw32/bin/ld.exe: C:\Users\ASUS\AppData\Local\Temp\ccgW0oJL.o: in function `main':
C:\Users\ASUS\Desktop\C++\GUI_Train\Libs/Test_output.cpp:7: undefined reference to `Simple_window::Simple_window(Graph_lib::Point, int, int, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)'
C:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/12.2.0/../../../../x86_64-w64-mingw32/bin/ld.exe: C:\Users\ASUS\Desktop\C++\GUI_Train\Libs/Test_output.cpp:14: undefined reference to `Simple_window::wait_for_button()'
C:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/12.2.0/../../../../x86_64-w64-mingw32/bin/ld.exe: C:\Users\ASUS\AppData\Local\Temp\ccgW0oJL.o:Test_output.cp:(.rdata$_ZTV13Simple_window[_ZTV13Simple_window]+0x20): undefined reference to `Graph_lib::Window::draw()'
C:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/12.2.0/../../../../x86_64-w64-mingw32/bin/ld.exe: C:\Users\ASUS\AppData\Local\Temp\ccgW0oJL.o:Test_output.cp:(.rdata$.refptr._ZTVN9Graph_lib6ButtonE[.refptr._ZTVN9Graph_lib6ButtonE]+0x0): undefined reference to `vtable for Graph_lib::Button'
C:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/12.2.0/../../../../x86_64-w64-mingw32/bin/ld.exe: C:\Users\ASUS\AppData\Local\Temp\ccgW0oJL.o:Test_output.cp:(.rdata$.refptr._ZTVN9Graph_lib6WindowE[.refptr._ZTVN9Graph_lib6WindowE]+0x0): undefined reference to `vtable for Graph_lib::Window'
this is my tasks:
{
"tasks": [
{
"type": "cppbuild",
"label": "C/C++: g++.exe build active file",
"command": "C:\\msys64\\mingw64\\bin\\g++.exe",
"args": [
"-fdiagnostics-color=always",
"-g",
"${file}",
"-lfltk",
"-o",
"${fileDirname}\\${fileBasenameNoExtension}.exe"
],
"options": {
"cwd": "${fileDirname}"
},
"problemMatcher": [
"$gcc"
],
"group": {
"kind": "build",
"isDefault": true
},
"detail": "Task generated by Debugger."
}
],
"version": "2.0.0"
}