Stroustrup 在使用 FLTK 时的 Header 错误

Question

我已经在 VS 2015 Community Edition 中成功安装了 FLTK。我正在处理其他 headers，Stroustrup 的书的一部分，以构建图形并创建自定义 windows 附加它们的位置。我的问题是当我尝试编译时收到 4 条错误消息（加上 23 条警告）：

(active) IntelliSense namespace "std" has no member "Vector" Win32Project1 c:\Users\Leonardo\Documents\Visual Studio 2015\Projects\Win32Project1\Win32Project1\Window.h 17

Error C2873 Build 'Vector': symbol cannot be used in a using-declaration Win32Project1 c:\users\leonardo\documents\visual studio 2015\projects\win32project1\win32project1\Window.h 17

Error C2039 Build 'Vector': is not a member of 'std' Win32Project1 c:\users\leonardo\documents\visual studio 2015\projects\win32project1\win32project1\Window.h 17

Error C2440 Build 'return': cannot convert from 'std::ifstream' to 'bool' Win32Project1 C:\Users\Leonardo\Documents\Visual Studio 2015\Projects\Win32Project1\Win32Project1\Graph.cpp 371

我按照本网站的步骤设置了一个 Win32Project（不是控制台项目）：http://www.c-jump.com/bcc/common/Talk2/Cxx/FltkInstallVC/FltkInstallVC.html。如果我运行测试示例它完美地工作，那么我猜，正确安装了附加库。

另外，作者提供的每一个header或者源文件我都添加到了项目中

main.cpp:

#include "std_lib_facilities.h"
#include "Graph.h"
#include "Simple_window.h"


int main()
{
    using namespace Graph_lib;

    Point tl{ 100,100 };

    Simple_window win{ tl,600,400,"My Window" };

    win.wait_for_button();

}

所有 header 和源文件都可以在以下位置找到：http://www.stroustrup.com/Programming/Programming-code.zip

这里Windows.h

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

#ifndef WINDOW_GUARD
#define WINDOW_GUARD

#include <string>
#include <vector>
#include <FL/Fl.H>
#include <FL/Fl_Window.H>
#include "Point.h"

using std::string;
using std::vector;

namespace Graph_lib
{
    class Shape;   // "forward declare" Shape
    class Widget;

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

    class Window : public Fl_Window { 
    public:
        // let the system pick the location:
        Window(int w, int h, const string& title);
        // top left corner in xy
        Window(Point xy, int w, int h, const string& title);    

        virtual ~Window() { }

        int x_max() const { return w; }
        int y_max() const { return h; }

        void resize(int ww, int hh) { w=ww, h=hh; size(ww,hh); }

        void set_label(const string& s) { copy_label(s.c_str()); }

        void attach(Shape& s) { shapes.push_back(&s); }
        void attach(Widget&);

        void detach(Shape& s);     // remove s from shapes 
        void detach(Widget& w);    // remove w from window (deactivates callbacks)

        void put_on_top(Shape& p); // put p on top of other shapes

    protected:
        void draw();

    private:
        vector<Shape*> shapes;     // shapes attached to window
        int w,h;                   // window size

        void init();
    };

和Graph.cpp

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

#include <FL/Fl_GIF_Image.H>
#include <FL/Fl_JPEG_Image.H>
#include "Graph.h"

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

namespace Graph_lib {

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

Shape::Shape() : 
    lcolor(fl_color()),      // default color for lines and characters
    ls(0),                   // default style
    fcolor(Color::invisible) // no fill
{}

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

void Shape::add(Point p)     // protected
{
    points.push_back(p);
}

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

void Shape::set_point(int i,Point p)        // not used; not necessary so far
{
    points[i] = p;
}

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

void Shape::draw_lines() const
{
    if (color().visibility() && 1<points.size())    // draw sole pixel?
        for (unsigned int i=1; i<points.size(); ++i)
            fl_line(points[i-1].x,points[i-1].y,points[i].x,points[i].y);
}

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

void Shape::draw() const
{
    Fl_Color oldc = fl_color();
    // there is no good portable way of retrieving the current style
    fl_color(lcolor.as_int());            // set color
    fl_line_style(ls.style(),ls.width()); // set style
    draw_lines();
    fl_color(oldc);      // reset color (to previous)
    fl_line_style(0);    // reset line style to default
}

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


void Shape::move(int dx, int dy)    // move the shape +=dx and +=dy
{
    for (int i = 0; i<points.size(); ++i) {
        points[i].x+=dx;
        points[i].y+=dy;
    }
}

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

Line::Line(Point p1, Point p2)    // construct a line from two points
{
    add(p1);    // add p1 to this shape
    add(p2);    // add p2 to this shape
}

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

void Lines::add(Point p1, Point p2)
{
    Shape::add(p1);
    Shape::add(p2);
}

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

// draw lines connecting pairs of points
void Lines::draw_lines() const
{
    if (color().visibility())
        for (int i=1; i<number_of_points(); i+=2)
            fl_line(point(i-1).x,point(i-1).y,point(i).x,point(i).y);
}

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

// does two lines (p1,p2) and (p3,p4) intersect?
// if se return the distance of the intersect point as distances from p1
inline pair<double,double> line_intersect(Point p1, Point p2, Point p3, Point p4, bool& parallel) 
{
    double x1 = p1.x;
    double x2 = p2.x;
    double x3 = p3.x;
    double x4 = p4.x;
    double y1 = p1.y;
    double y2 = p2.y;
    double y3 = p3.y;
    double y4 = p4.y;

    double denom = ((y4 - y3)*(x2-x1) - (x4-x3)*(y2-y1));
    if (denom == 0){
        parallel= true;
        return pair<double,double>(0,0);
    }
    parallel = false;
    return pair<double,double>( ((x4-x3)*(y1-y3) - (y4-y3)*(x1-x3))/denom,
                                ((x2-x1)*(y1-y3) - (y2-y1)*(x1-x3))/denom);
}

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

//intersection between two line segments
//Returns true if the two segments intersect,
//in which case intersection is set to the point of intersection
bool line_segment_intersect(Point p1, Point p2, Point p3, Point p4, Point& intersection){
   bool parallel;
   pair<double,double> u = line_intersect(p1,p2,p3,p4,parallel);
   if (parallel || u.first < 0 || u.first > 1 || u.second < 0 || u.second > 1) return false;
   intersection.x = p1.x + u.first*(p2.x - p1.x);
   intersection.y = p1.y + u.first*(p2.y - p1.y);
   return true;
}

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

void Polygon::add(Point p)
{
    int np = number_of_points();

    if (1<np) {    // check that thenew line isn't parallel to the previous one
        if (p==point(np-1)) error("polygon point equal to previous point");
        bool parallel;
        line_intersect(point(np-1),p,point(np-2),point(np-1),parallel);
        if (parallel)
            error("two polygon points lie in a straight line");
    }

    for (int i = 1; i<np-1; ++i) {    // check that new segment doesn't interset and old point
        Point ignore(0,0);
        if (line_segment_intersect(point(np-1),p,point(i-1),point(i),ignore))
            error("intersect in polygon");
    }
    

    Closed_polyline::add(p);
}

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

void Polygon::draw_lines() const
{
    if (number_of_points() < 3) error("less than 3 points in a Polygon");
    Closed_polyline::draw_lines();
}

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

void Open_polyline::draw_lines() const
{
    if (fill_color().visibility()) {
        fl_color(fill_color().as_int());
        fl_begin_complex_polygon();
        for(int i=0; i<number_of_points(); ++i){
            fl_vertex(point(i).x, point(i).y);
        }
        fl_end_complex_polygon();
        fl_color(color().as_int());    // reset color
    }
    
    if (color().visibility())
        Shape::draw_lines();
}

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

void Closed_polyline::draw_lines() const
{
    Open_polyline::draw_lines();    // first draw the "open poly line part"
    // then draw closing line:
    if (color().visibility())
        fl_line(point(number_of_points()-1).x, 
        point(number_of_points()-1).y,
        point(0).x,
        point(0).y);
}

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

void draw_mark(Point xy, char c)
{
    static const int dx = 4;
    static const int dy = 4;

    string m(1,c);
    fl_draw(m.c_str(),xy.x-dx,xy.y+dy);
}

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

void Marked_polyline::draw_lines() const
{
    Open_polyline::draw_lines();
    for (int i=0; i<number_of_points(); ++i) 
        draw_mark(point(i),mark[i%mark.size()]);
}

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

void Rectangle::draw_lines() const
{
    if (fill_color().visibility()) {    // fill
        fl_color(fill_color().as_int());
        fl_rectf(point(0).x,point(0).y,w,h);
    }

    if (color().visibility()) {    // lines on top of fill
        fl_color(color().as_int());
        fl_rect(point(0).x,point(0).y,w,h);
    }
}

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

Circle::Circle(Point p, int rr)    // center and radius
:r(rr)
{
    add(Point(p.x-r,p.y-r));       // store top-left corner
}

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

Point Circle::center() const
{
    return Point(point(0).x+r, point(0).y+r);
}

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

void Circle::draw_lines() const
{
    if (color().visibility())
        fl_arc(point(0).x,point(0).y,r+r,r+r,0,360);
}

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

void Ellipse::draw_lines() const
{
    if (color().visibility())
        fl_arc(point(0).x,point(0).y,w+w,h+h,0,360);
}

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

void Text::draw_lines() const
{
    int ofnt = fl_font();
    int osz = fl_size();
    fl_font(fnt.as_int(),fnt_sz);
    fl_draw(lab.c_str(),point(0).x,point(0).y);
    fl_font(ofnt,osz);
}

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

Axis::Axis(Orientation d, Point xy, int length, int n, string lab) :
    label(Point(0,0),lab)
{
    if (length<0) error("bad axis length");
    switch (d){
    case Axis::x:
    {
        Shape::add(xy); // axis line
        Shape::add(Point(xy.x+length,xy.y));

        if (1<n) {      // add notches
            int dist = length/n;
            int x = xy.x+dist;
            for (int i = 0; i<n; ++i) {
                notches.add(Point(x,xy.y),Point(x,xy.y-5));
                x += dist;
            }
        }
        // label under the line
        label.move(length/3,xy.y+20);
        break;
    }
    case Axis::y:
    {
        Shape::add(xy); // a y-axis goes up
        Shape::add(Point(xy.x,xy.y-length));

        if (1<n) {      // add notches
            int dist = length/n;
            int y = xy.y-dist;
            for (int i = 0; i<n; ++i) {
                notches.add(Point(xy.x,y),Point(xy.x+5,y));
                y -= dist;
            }
        }
        // label at top
        label.move(xy.x-10,xy.y-length-10);
        break;
    }
    case Axis::z:
        error("z axis not implemented");
    }
}

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

void Axis::draw_lines() const
{
    Shape::draw_lines();
    notches.draw();  // the notches may have a different color from the line
    label.draw();    // the label may have a different color from the line
}

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

void Axis::set_color(Color c)
{
    Shape::set_color(c);
    notches.set_color(c);
    label.set_color(c);
}

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

void Axis::move(int dx, int dy)
{
    Shape::move(dx,dy);
    notches.move(dx,dy);
    label.move(dx,dy);
}

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

Function::Function(Fct f, double r1, double r2, Point xy,
                   int count, double xscale, double yscale)
// graph f(x) for x in [r1:r2) using count line segments with (0,0) displayed at xy
// x coordinates are scaled by xscale and y coordinates scaled by yscale
{
    if (r2-r1<=0) error("bad graphing range");
    if (count <=0) error("non-positive graphing count");
    double dist = (r2-r1)/count;
    double r = r1;
    for (int i = 0; i<count; ++i) {
        add(Point(xy.x+int(r*xscale),xy.y-int(f(r)*yscale)));
        r += dist;
    }
}

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

bool can_open(const string& s)
// check if a file named s exists and can be opened for reading
{
    ifstream ff(s.c_str());
    return ff;
}

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

#define ARRAY_SIZE(a) (sizeof(a)/sizeof((a)[0]))

Suffix::Encoding get_encoding(const string& s)
{
    struct SuffixMap 
    { 
        const char*      extension;
        Suffix::Encoding suffix;
    };

    static SuffixMap smap[] = {
        {".jpg",  Suffix::jpg},
        {".jpeg", Suffix::jpg},
        {".gif",  Suffix::gif},
    };

    for (int i = 0, n = ARRAY_SIZE(smap); i < n; i++)
    {
        int len = strlen(smap[i].extension);

        if (s.length() >= len && s.substr(s.length()-len, len) == smap[i].extension)
            return smap[i].suffix;
    }

    return Suffix::none;
}

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

// somewhat over-elaborate constructor
// because errors related to image files can be such a pain to debug
Image::Image(Point xy, string s, Suffix::Encoding e)
    :w(0), h(0), fn(xy,"")
{
    add(xy);

    if (!can_open(s)) {    // can we open s?
        fn.set_label("cannot open \""+s+'\"');
        p = new Bad_image(30,20);    // the "error image"
        return;
    }

    if (e == Suffix::none) e = get_encoding(s);

    switch(e) {        // check if it is a known encoding
    case Suffix::jpg:
        p = new Fl_JPEG_Image(s.c_str());
        break;
    case Suffix::gif:
        p = new Fl_GIF_Image(s.c_str());
        break;
    default:    // Unsupported image encoding
        fn.set_label("unsupported file type \""+s+'\"');
        p = new Bad_image(30,20);    // the "error image"
    }
}

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

void Image::draw_lines() const
{
    if (fn.label()!="") fn.draw_lines();

    if (w&&h)
        p->draw(point(0).x,point(0).y,w,h,cx,cy);
    else
        p->draw(point(0).x,point(0).y);
}

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

} // of namespace Graph_lib

希望有人能帮助我。

编辑

    /*
std_lib_facilities.h
*/

/*
    simple "Programming: Principles and Practice using C++ (second edition)" course header to
    be used for the first few weeks.
    It provides the most common standard headers (in the global namespace)
    and minimal exception/error support.

    Students: please don't try to understand the details of headers just yet.
    All will be explained. This header is primarily used so that you don't have
    to understand every concept all at once.

    By Chapter 10, you don't need this file and after Chapter 21, you'll understand it

    Revised April 25, 2010: simple_error() added
    
    Revised November 25 2013: remove support for pre-C++11 compilers, use C++11: <chrono>
    Revised November 28 2013: add a few container algorithms
    Revised June 8 2014: added #ifndef to workaround Microsoft C++11 weakness
*/

#ifndef H112
#define H112 251113L


#include<iostream>
#include<iomanip>
#include<fstream>
#include<sstream>
#include<cmath>
#include<cstdlib>
#include<string>
#include<list>
#include <forward_list>
#include<vector>
#include<unordered_map>
#include<algorithm>
#include <array>
#include <regex>
#include<random>
#include<stdexcept>

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


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

typedef long Unicode;

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

using namespace std;

template<class T> string to_string(const T& t)
{
    ostringstream os;
    os << t;
    return os.str();
}

struct Range_error : out_of_range { // enhanced vector range error reporting
    int index;
    Range_error(int i) :out_of_range("Range error: "+to_string(i)), index(i) { }
};


// trivially range-checked vector (no iterator checking):
template< class T> struct Vector : public std::vector<T> {
    using size_type = typename std::vector<T>::size_type;

#ifdef _MSC_VER
    // microsoft doesn't yet support C++11 inheriting constructors
    Vector() { }
    explicit Vector(size_type n) :std::vector<T>(n) {}
    Vector(size_type n, const T& v) :std::vector<T>(n,v) {}
    template <class I>
    Vector(I first, I last) : std::vector<T>(first, last) {}
    Vector(initializer_list<T> list) : std::vector<T>(list) {}
#else
    using std::vector<T>::vector;   // inheriting constructor
#endif

    T& operator[](unsigned int i) // rather than return at(i);
    {
        if (i<0||this->size()<=i) throw Range_error(i);
        return std::vector<T>::operator[](i);
    }
    const T& operator[](unsigned int i) const
    {
        if (i<0||this->size()<=i) throw Range_error(i);
        return std::vector<T>::operator[](i);
    }
};

// disgusting macro hack to get a range checked vector:
#define vector Vector

// trivially range-checked string (no iterator checking):
struct String : std::string {
    using size_type = std::string::size_type;
//  using string::string;

    char& operator[](unsigned int i) // rather than return at(i);
    {
        if (i<0||size()<=i) throw Range_error(i);
        return std::string::operator[](i);
    }

    const char& operator[](unsigned int i) const
    {
        if (i<0||size()<=i) throw Range_error(i);
        return std::string::operator[](i);
    }
};


namespace std {

    template<> struct hash<String>
    {
        size_t operator()(const String& s) const
        {
            return hash<std::string>()(s);
        }
    };

} // of namespace std


struct Exit : runtime_error {
    Exit(): runtime_error("Exit") {}
};

// error() simply disguises throws:
inline void error(const string& s)
{
    throw runtime_error(s);
}

inline void error(const string& s, const string& s2)
{
    error(s+s2);
}

inline void error(const string& s, int i)
{
    ostringstream os;
    os << s <<": " << i;
    error(os.str());
}


template<class T> char* as_bytes(T& i)  // needed for binary I/O
{
    void* addr = &i;    // get the address of the first byte
                        // of memory used to store the object
    return static_cast<char*>(addr); // treat that memory as bytes
}


inline void keep_window_open()
{
    cin.clear();
    cout << "Please enter a character to exit\n";
    char ch;
    cin >> ch;
    return;
}

inline void keep_window_open(string s)
{
    if (s=="") return;
    cin.clear();
    cin.ignore(120,'\n');
    for (;;) {
        cout << "Please enter " << s << " to exit\n";
        string ss;
        while (cin >> ss && ss!=s)
            cout << "Please enter " << s << " to exit\n";
        return;
    }
}



// error function to be used (only) until error() is introduced in Chapter 5:
inline void simple_error(string s)  // write ``error: s and exit program
{
    cerr << "error: " << s << '\n';
    keep_window_open();     // for some Windows environments
    exit(1);
}

// make std::min() and std::max() accessible on systems with antisocial macros:
#undef min
#undef max


// run-time checked narrowing cast (type conversion). See ???.
template<class R, class A> R narrow_cast(const A& a)
{
    R r = R(a);
    if (A(r)!=a) error(string("info loss"));
    return r;
}

// random number generators. See 24.7.



inline int randint(int min, int max) { static default_random_engine ran; return uniform_int_distribution<>{min, max}(ran); }

inline int randint(int max) { return randint(0, max); }

//inline double sqrt(int x) { return sqrt(double(x)); } // to match C++0x

// container algorithms. See 21.9.

template<typename C>
using Value_type = typename C::value_type;

template<typename C>
using Iterator = typename C::iterator;

template<typename C>
    // requires Container<C>()
void sort(C& c)
{
    std::sort(c.begin(), c.end());
}

template<typename C, typename Pred>
// requires Container<C>() && Binary_Predicate<Value_type<C>>()
void sort(C& c, Pred p)
{
    std::sort(c.begin(), c.end(), p);
}

template<typename C, typename Val>
    // requires Container<C>() && Equality_comparable<C,Val>()
Iterator<C> find(C& c, Val v)
{
    return std::find(c.begin(), c.end(), v);
}

template<typename C, typename Pred>
// requires Container<C>() && Predicate<Pred,Value_type<C>>()
Iterator<C> find_if(C& c, Pred p)
{
    return std::find_if(c.begin(), c.end(), p);
}

#endif //H112

Answer 1

Error C2440 Build 'return': cannot convert from 'std::ifstream' to 'bool' Win32Project1 C:\Users\Leonardo\Documents\Visual Studio 2015\Projects\Win32Project1\Win32Project1\Graph.cpp 371

我怀疑您运行正在接受 C++11 引入的重大更改。代码似乎是这样的：

bool can_open(const string& s)
// check if a file named s exists and can be opened for reading
{
    ifstream ff(s.c_str());
    return ff;
}

该代码过去使用 operator void * 将 ff 从 istream 转换为 void *，然后再转换为 bool。如果 ifstream 错误，则转换为 void * 将导致一个空指针，该指针又将被视为 bool false。

但是 C++11 为流引入了 explicit operator bool()（并去掉了 void * 运算符？）。由于 bool 运算符是 explicit，因此该运算符不会用于隐式转换。

要can_open使用 C++11 版本的流进行编译，您需要显式进行转换：

bool can_open(const string& s)
// check if a file named s exists and can be opened for reading
{
    ifstream ff(s.c_str());
    return (bool)ff;
}

但是，如果使用 C++11 之前版本的流进行编译，该更改将破坏代码。

Stroustrup 在使用 FLTK 时的 Header 错误

Stroustrup's Header error working with FLTK

c++

visual-studio-2015

fltk