c++ - 无法编译应该从 Bjarne stroustrup 的编程原理和实践的第 12 章工作的图形代码

Question

你好堆栈溢出的成员!我希望曾经去过我所在的地方的人可以为我指明正确的方向。
我目前正在学习 C++ 并进行第 12 章中的图形练习，但我似乎无法获得应该可以工作的代码。
几天来，我一直在尝试让任何代码正常工作，并且已经克服了一些大问题，但是由于我只学习 C++，所以我目前处于我的专业知识的极限，并且已经用尽了以前在各个论坛上提出的所有问题，这些问题实际上解决了我遇到的许多其他问题。
这是简单的图形代码，下面是我收到的大量错误消息:

//
// This is example code from Chapter 12.3 "A first example" of
// "Programming -- Principles and Practice Using C++" by Bjarne Stroustrup
//

#include <PPP2HEADERS/Simple_window.h>// get access to our window library
#include <PPP2HEADERS/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

    Graph_lib::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
}

//------------------------------------------------------------------------------

尝试编译时收到的错误消息:

1>------ Build started: Project: test2, Configuration: Debug Win32 ------
1>test4.cpp
1>C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Auxiliary\VS\include\PPP2HEADERS\Graph.h(45,10): warning C4305: 'initializing': truncation from 'Graph_lib::Color::Transparency' to 'char'
1>C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Auxiliary\VS\include\PPP2HEADERS\Graph.h(45,46): warning C4309: 'initializing': truncation of constant value
1>C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Auxiliary\VS\include\PPP2HEADERS\Graph.h(47,10): warning C4305: 'initializing': truncation from 'Graph_lib::Color::Transparency' to 'char'
1>C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Auxiliary\VS\include\PPP2HEADERS\Graph.h(47,39): warning C4309: 'initializing': truncation of constant value
1>C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Auxiliary\VS\include\PPP2HEADERS\GUI.h(107,39): warning C4018: '<': signed/unsigned mismatch
1>C:\Users\darai\Documents\PPP C++ CODE\chapter12_graphics_example\test2\test4.cpp(16,23): error C2440: 'initializing': cannot convert from 'initializer list' to 'Graph_lib::Point'
1>C:\Users\darai\Documents\PPP C++ CODE\chapter12_graphics_example\test2\test4.cpp(16,23): message : No constructor could take the source type, or constructor overload resolution was ambiguous
1>C:\Users\darai\Documents\PPP C++ CODE\chapter12_graphics_example\test2\test4.cpp(22,28): error C2440: '<function-style-cast>': cannot convert from 'initializer list' to 'Graph_lib::Point'
1>C:\Users\darai\Documents\PPP C++ CODE\chapter12_graphics_example\test2\test4.cpp(22,28): message : No constructor could take the source type, or constructor overload resolution was ambiguous
1>C:\Users\darai\Documents\PPP C++ CODE\chapter12_graphics_example\test2\test4.cpp(23,28): error C2440: '<function-style-cast>': cannot convert from 'initializer list' to 'Graph_lib::Point'
1>C:\Users\darai\Documents\PPP C++ CODE\chapter12_graphics_example\test2\test4.cpp(23,28): message : No constructor could take the source type, or constructor overload resolution was ambiguous
1>C:\Users\darai\Documents\PPP C++ CODE\chapter12_graphics_example\test2\test4.cpp(24,28): error C2440: '<function-style-cast>': cannot convert from 'initializer list' to 'Graph_lib::Point'
1>C:\Users\darai\Documents\PPP C++ CODE\chapter12_graphics_example\test2\test4.cpp(24,28): message : No constructor could take the source type, or constructor overload resolution was ambiguous
1>Done building project "test2.vcxproj" -- FAILED.
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

我很确定 FLTK 安装正确，因为在本书的附录 D 中有一个示例代码可以编译，而且我也使用提到的更新的头文件 here .
在这一点上，我已经尝试让图形代码工作好几天了，我想知道学习这本书的图形部分是否是绝对必要的。
如果我违反了任何规则，任何人都可以提供任何帮助，我们将不胜感激并道歉，这是我第一次发布到堆栈溢出。
谢谢你。
Point.H 按要求:

//
// This is a GUI support code to the chapters 12-16 of the book
// "Programming -- Principles and Practice Using C++" by Bjarne Stroustrup
//

#ifndef POINT_GUARD
#define POINT_GUARD

namespace Graph_lib {
//------------------------------------------------------------------------------

struct Point {
    int x, y;
};

//------------------------------------------------------------------------------

inline bool operator==(Point a, Point b) { return a.x==b.x && a.y==b.y; } 

//------------------------------------------------------------------------------

inline bool operator!=(Point a, Point b) { return !(a==b); }

//------------------------------------------------------------------------------

}
#endif // POINT_GUARD

Answer 1

假设以下目录布局，根据需要进行调整。还假设 fltk\lib 中的 FLTK 库已成功构建，例如Install-FLTK-for-use-with-Visual-C .

X:\ppp2code
├─fltk     <--  FLTK root directory, based on fltk-1.3.5-source
│ ├─FL     <--       include directory
│ └─lib    <--       lib directory, with the prebuilt libraries
├─gui      <--  PPP2 GUI (simple_window etc), based on stroustrup.com/programming_support.html 
└─test4    <--  OP's test code

替换 #include <PPP2HEADERS/Simple_window.h>与 #include <Simple_window.h>在 test4.cpp , 和类似的 #include <PPP2HEADERS/Graph.h>与 #include <Graph.h> .

打开 VS 2019 的 x86 Native Tools 命令提示符 (cmd /k vcvars32.bat)，当前目录设置为 X:\ppp2code .

使用 /W3 编译避免由 /W4 触发的(大部分是无害的)警告.

X:\ppp2code\test4>cl.exe /c /nologo /W3 /D "WIN32" /MD /EHsc /O2 /I "..\gui" /I "..\fltk" test4.cpp ..\gui\*.cpp

与支持的 PPP2 对象和预构建的 FLTK 库链接。

X:\ppp2code\test4>link /nologo /LIBPATH:"..\fltk\lib" /SUBSYSTEM:WINDOWS /OUT:"test4.exe" test4.obj graph.obj gui.obj simple_window.obj window.obj fltk.lib fltkimages.lib fltkjpeg.lib user32.lib gdi32.lib shell32.lib advapi32.lib ole32.lib

运行结果 test4.exe .