Question

我是编程新手，我是一名开始学习C ++的学生。我想通过一本关于C ++，编程原理和编程的好书来领先我的课程。我为此推荐了练习（第2版）。我正在进行第一个名为“Hello，World！”的练习。我因为一些编译错误而陷入困境。（我正在使用Visual Studio 2015）。

当我尝试运行程序输出时显示此

1>------ Rebuild All started: Project: Hello,World!, Configuration: Debug Win32 ------
1>  Hello,World!.cpp
1>MSVCRTD.lib(exe_main.obj) : error LNK2019: unresolved external symbol _main referenced in function "int __cdecl invoke_main(void)" (?invoke_main@@YAHXZ)
1>F:\DAE v2015\1) Programming\C++ Projects\Hello,World!\Debug\Hello,World!.exe : fatal error LNK1120: 1 unresolved externals
========== Rebuild All: 0 succeeded, 1 failed, 0 skipped ==========

他的头文件的代码如下：

/*
   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

提前感谢您的帮助！ PS：如果你认为我应该从另一本书开始，因为我可能会遇到更多像这样的问题，请告诉我：）

Answer 1

使用代码将main.cpp文件添加到项目中，如果它编写的第一个c ++程序必须只包含此代码。

#include <iostream>
#include <conio.h>

int main() {

    std::cout << "Hello, World!" << std::endl;
    _getch();
    return 0;
}

第1课）所有c ++程序必须包含main()函数实现。

personaly，我用C Teach Yourself C++ in 24 hours

开始了我在C ++中的第一步

在我看来，对于C ++新手来说，Bjarne的书很难阅读

Answer 2

当我删除行#include "stdafx.h"时会发生这种情况谢谢你们的帮助：D对不起，我很糟糕。

'Hello,World!.exe' (Win32): Loaded 'F:\DAE v2015\1) Programming\C++ Projects\Hello,World!\Debug\Hello,World!.exe'. Symbols loaded.
'Hello,World!.exe' (Win32): Loaded 'C:\Windows\SysWOW64\ntdll.dll'. Cannot find or open the PDB file.
'Hello,World!.exe' (Win32): Loaded 'C:\Windows\SysWOW64\kernel32.dll'. Cannot find or open the PDB file.
'Hello,World!.exe' (Win32): Loaded 'C:\Windows\SysWOW64\KernelBase.dll'. Cannot find or open the PDB file.
'Hello,World!.exe' (Win32): Loaded 'C:\Windows\SysWOW64\msvcp140d.dll'. Cannot find or open the PDB file.
'Hello,World!.exe' (Win32): Loaded 'C:\Windows\SysWOW64\vcruntime140d.dll'. Cannot find or open the PDB file.
'Hello,World!.exe' (Win32): Loaded 'C:\Windows\SysWOW64\ucrtbased.dll'. Cannot find or open the PDB file.
'Hello,World!.exe' (Win32): Loaded 'C:\Windows\SysWOW64\advapi32.dll'. Cannot find or open the PDB file.
'Hello,World!.exe' (Win32): Loaded 'C:\Windows\SysWOW64\msvcrt.dll'. Cannot find or open the PDB file.
'Hello,World!.exe' (Win32): Loaded 'C:\Windows\SysWOW64\sechost.dll'. Cannot find or open the PDB file.
'Hello,World!.exe' (Win32): Loaded 'C:\Windows\SysWOW64\rpcrt4.dll'. Cannot find or open the PDB file.
'Hello,World!.exe' (Win32): Loaded 'C:\Windows\SysWOW64\cryptbase.dll'. Cannot find or open the PDB file.
'Hello,World!.exe' (Win32): Loaded 'C:\Windows\SysWOW64\sspicli.dll'. Cannot find or open the PDB file.
'Hello,World!.exe' (Win32): Loaded 'C:\Windows\SysWOW64\bcryptprimitives.dll'. Cannot find or open the PDB file.
'Hello,World!.exe' (Win32): Loaded 'C:\Windows\SysWOW64\kernel.appcore.dll'. Cannot find or open the PDB file.
The program '[892] Hello,World!.exe' has exited with code 0 (0x0).

Bjarne Stroustrup的头文件编译错误（PPP2 - 编程原理和实践）

2 个答案: