我正在尝试在 C++ MSVS2010 中编译该程序，但遇到了奇怪的编译器错误，例如
Error 12 error LNK1120: 1 unresolved externals C:\Users\win7vm\Documents\Visual Studio 2010\Projects\WinDemo \Debug\WinDemo.exe 1.
我也得到了
Error 11 error LNK2019: unresolved external symbol "public: int __thiscall Dice::returnRoll(void)" (?returnRoll@Dice@@QAEHXZ) referenced in function "public: void __thiscall Dice::drawSpots(struct HDC__ *,int,int,int,int,int,int,int)" (?drawSpots@Dice@@QAEXPAUHDC__@@HHHHHHH@Z) C:\Users\win7vm\Documents\Visual Studio 2010\Projects\WinDemo \WinDemo \Debug\WinDemo.exe 1\Dice.obj
两者似乎都与语法无关，我并不完全理解它们。基本上，这个想法是让 switch 语句显示从另一个函数传递到该函数的值。我几乎可以肯定这是一个简单的参考/指针问题，我完全错过了。这个类有一个头文件，一个 windows.h（开箱即用，未经修改，因此您可以在需要时查找它），以及带有主文件的函数（此处包含函数和类）。让我预先回答 2 个几乎肯定会出现的问题：a) 是的，它绝对必须使用 c++ 中的 windows.h 文件。b) 是的，我知道有一百个更好的库和语言可以用来解决这个问题，我在这件事上别无选择。也有人可能会尝试指出声明的全局变量。在对相对较短的代码块进行故障排除时，全局变量是暂时但必要的不便。我意识到你们中的许多人在 C++ 方面都非常熟练，但我要求你们耐心地解释我的 C++ 编程水平较低的答案。谢谢你。:)
** //头文件
#include <windows.h>
#include <math.h>
#include <vector>
using namespace std;
int count=0;
int *result = &count;
class Dice
{
public:
void drawSpots(HDC hdc, int x1,int y1, int x2,int y2, int r, int g,int b);
int roll();
wchar_t * drawString();
int returnRoll();
private:
int x1,x2,y1,y2,sr,sg,sb;
//int &count;
//int *result;
int value;
int spotColor;
};
//definitions file
void Dice::drawSpots(HDC hdc, int x1,int y1, int x2,int y2, int r, int g,int b)
{
*result = roll();
//vectorOfDice.push_back(result);
//wchar_t * drawString();
returnRoll();
HBRUSH hBrush = CreateSolidBrush(RGB(r,g,b));
SelectObject(hdc,hBrush);
switch(*result)
{
case 1:
//draw something based on case
break;
case 2:
//draw something based on case
break;
case 3:
//draw something based on case
break;
case 4:
//draw something based on case
break;
case 5:
//draw something based on case
break;
case 6:
//draw something based on case
break;
}
DeleteObject(hBrush);
}
int Dice::roll()
{
value=1+(rand()%6);
return value;
}
int Dice::returnRoll()
{
count=0;
if((*result == 2)||(*result == 4)||(*result == 6))
{
count++;
}
return count;
}
wchar_t * Dice::drawString()
{
//result = returnRoll(result);
//result = roll();
switch(*result)
{
case 0:
return L"no";
break;
case 1:
return L"1";
break;
case 2:
return L"2";
break;
case 3:
return L"3";
break;
case 4:
return L"4";
break;
case 5:
return L"5";
break;
case 6:
return L"6";
break;
}
return L"X";
}
//main file
#include <windows.h>
#include <math.h>
#include "Dice.h"
const wchar_t g_szClassName[] = L"myWindowClass";
// Step 4: the Window Procedure
LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
Dice dice;
//state variables
static int red = 0;
static int green = 0;
static int blue = 100;
static int tr = 0;
static int tg = 0;
static int tb = 0;
HDC hDC;
PAINTSTRUCT Ps;
HPEN hPen1;
HPEN hPen2;
HBRUSH hBrush1;
HFONT hFont1;
RECT rect;
int fontHeight = 100;
switch(msg)
{
case WM_PAINT:
hDC = BeginPaint(hwnd,&Ps);
hPen1=CreatePen(PS_SOLID,5,RGB(red,green,blue));
hPen2=CreatePen(PS_SOLID,5,RGB(0,0,0));
hBrush1= CreateSolidBrush(RGB(0,0,255));
SelectObject(hDC,hPen1);
SelectObject(hDC,hBrush1);
fontHeight=50;
hFont1=CreateFont(fontHeight,0,0,0,0,1,0,0,0,0,0,0,0,L"Times New Roman");
//hFont1=CreateFont(fontHeight,0,0,0,0,0,0,0,0,0,0,0,0,L"Arial");
SelectObject(hDC,hFont1);
rect.top=100;
rect.bottom=700;
rect.left = 550;
rect.right =950;
DrawText(hDC,L"There are ",-1,&rect,DT_CENTER | DT_WORDBREAK );
rect.top=200;
DrawText(hDC,dice.drawString(),-1,&rect,DT_CENTER | DT_WORDBREAK );
rect.top=300;
DrawText(hDC,L" even dice!",-1,&rect,DT_CENTER | DT_WORDBREAK );
DeleteObject(hBrush1);
DeleteObject(hPen2);
DeleteObject(hPen1);
EndPaint(hwnd,&Ps);
break;
case WM_KEYDOWN:
if(wParam==VK_SPACE)
{
dice.roll();
InvalidateRect(hwnd,NULL,true);
}
break;
case WM_CHAR:
if(wParam=='c')
{
tr=rand()%256;
tg=rand()%256;
tb=rand()%256;
dice.spotColors();
}
InvalidateRect(hwnd,NULL,true);
break;
case WM_CLOSE:
DestroyWindow(hwnd);
break;
case WM_DESTROY:
PostQuitMessage(0);
break;
default:
return DefWindowProc(hwnd, msg, wParam, lParam);
}
return 0;
}
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
LPSTR lpCmdLine, int nCmdShow)
{
WNDCLASSEX wc;
HWND hwnd;
MSG Msg;
//Step 1: Registering the Window Class
wc.cbSize = sizeof(WNDCLASSEX);
wc.style = 0;
wc.lpfnWndProc = WndProc;
wc.cbClsExtra = 0;
wc.cbWndExtra = 0;
wc.hInstance = hInstance;
wc.hIcon = LoadIcon(NULL, IDI_APPLICATION);
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
wc.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
wc.lpszMenuName = NULL;
wc.lpszClassName = g_szClassName;
wc.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
if(!RegisterClassEx(&wc))
{
MessageBox(NULL, L"Window Registration Failed!", L"Error!",
MB_ICONEXCLAMATION | MB_OK);
return 0;
}
// Step 2: Creating the Window
hwnd = CreateWindowEx(
WS_EX_CLIENTEDGE,
g_szClassName,
L"window",
WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT, CW_USEDEFAULT, 1000, 800,
NULL, NULL, hInstance, NULL);
if(hwnd == NULL)
{
MessageBox(NULL, L"Window Creation Failed!", L"Error!",
MB_ICONEXCLAMATION | MB_OK);
return 0;
}
ShowWindow(hwnd, nCmdShow);
UpdateWindow(hwnd);
// Step 3: The Message Loop
while(GetMessage(&Msg, NULL, 0, 0) > 0)
{
TranslateMessage(&Msg);
DispatchMessage(&Msg);
}
return Msg.wParam;
}
**
编辑：是的，谢谢我收到链接器错误，但是将 Dice:: 添加到签名（似乎减少了编译器的抱怨但是）我仍然收到类似的不寻常错误，例如 -
Error 11 error LNK1169: one or more multiply defined symbols found C:\Users\win7vm\Documents\Visual Studio 2010\Projects\\WinDemo \Debug\WinDemo.exe 1
Error 10 error LNK2005: "int * result" (?result@@3PAHA) already defined in Dice.obj C:\Users\win7vm\Documents\Visual Studio 2010\Projects\WinDemo \WinDemo \main.obj
Error 9 error LNK2005: "int count" (?count@@3HA) already defined in Dice.obj C:\Users\win7vm\Documents\Visual Studio 2010\Projects\WinDemo \WinDemo \main.obj