Question

我编译它，它运行然后我重新打开它并且不再工作了。这发生在devc ++ 5.8.3和codeblocks。

我的代码（评论默认来自IDE）：

    #include <windows.h>
    #include <cmath>
    #include <cstdlib>

    HPEN hPen;
    HDC hDC;
    PAINTSTRUCT Ps;

    void DrawLine(int x1, int y1, int x2, int y2, HPEN pen){
        SelectObject(hDC,pen);
        MoveToEx(hDC,x1,y1,NULL);
        LineTo(hDC,x2,y2);
    }
    void Draw(int originx, int originy, float value,int handlength){
        DrawLine(originx, originy, (handlength*cos(value*180/3.14))+originx, (handlength*sin(value*180/3.14))+originy,hPen);
        DrawLine(originx, originy, -(handlength*cos(value*180/3.14))+originx, -(handlength*sin(value*180/3.14))+originy,hPen);
    }
    /* This is where all the input to the window goes to */
    LRESULT CALLBACK WndProc(HWND hwnd, UINT Message, WPARAM wParam, LPARAM lParam) {
        switch(Message) {

            /* Upon destruction, tell the main thread to stop */
            case WM_DESTROY: {
                PostQuitMessage(0);
                break;
            }
            case WM_PAINT: {
                int r;
                int g;
                int b;
                hDC = BeginPaint(hwnd, &Ps);
                for(int i=0;i<170;i=i+1){   
                r = rand() % 256;
                g = rand() % 256;
                b = rand() % 256;
                Sleep(10);
                hPen = CreatePen(PS_INSIDEFRAME, 1, RGB(r, g, b));
                Draw(320,240,i,180);

                }       
                EndPaint(hwnd, &Ps);
                break;
            }
            /* All other messages (a lot of them) are processed using default procedures */
            default:
                return DefWindowProc(hwnd, Message, wParam, lParam);
        }
        return 0;
    }

    /* The 'main' function of Win32 GUI programs: this is where execution starts */
    int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow) {
        WNDCLASSEX wc; /* A properties struct of our window */
        HWND hwnd; /* A 'HANDLE', hence the H, or a pointer to our window */
        MSG msg; /* A temporary location for all messages */

        /* zero out the struct and set the stuff we want to modify */
        memset(&wc,0,sizeof(wc));
        wc.cbSize        = sizeof(WNDCLASSEX);
        wc.lpfnWndProc   = WndProc; /* This is where we will send messages to */
        wc.hInstance     = hInstance;
        wc.hCursor       = LoadCursor(NULL, IDC_ARROW);

        /* White, COLOR_WINDOW is just a #define for a system color, try Ctrl+Clicking it */
        wc.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
        wc.lpszClassName = "WindowClass";
        wc.hIcon         = LoadIcon(NULL, IDI_APPLICATION); /* Load a standard icon */
        wc.hIconSm       = LoadIcon(NULL, IDI_APPLICATION); /* use the name "A" to use the project icon */

        if(!RegisterClassEx(&wc)) {
            MessageBox(NULL, "Window Registration Failed!","Error!",MB_ICONEXCLAMATION|MB_OK);
            return 0;
        }

        hwnd = CreateWindowEx(WS_EX_CLIENTEDGE,"WindowClass","Lines",WS_VISIBLE|WS_OVERLAPPEDWINDOW,
            CW_USEDEFAULT, /* x */
            CW_USEDEFAULT, /* y */
            640, /* width */
            480, /* height */
            NULL,NULL,hInstance,NULL);

        if(hwnd == NULL) {
            MessageBox(NULL, "Window Creation Failed!","Error!",MB_ICONEXCLAMATION|MB_OK);
            return 0;
        }

        /*
            This is the heart of our program where all input is processed and 
            sent to WndProc. Note that GetMessage blocks code flow until it receives something, so
            this loop will not produce unreasonably high CPU usage
        */
        while(GetMessage(&msg, NULL, 0, 0) > 0) { /* If no error is received... */
            TranslateMessage(&msg); /* Translate key codes to chars if present */
            DispatchMessage(&msg); /* Send it to WndProc */
        }

        return msg.wParam;
    }

编译日志：

C ++编译器：C：\ Program Files（x86）\ Dev-Cpp \ MinGW64 \ bin \ g ++。exe

命令：g ++。exe＆＃34; C：\ Users \ Pall \ Desktop \ proj1 \ lines.cpp＆＃34; -o＆＃34; C：\ Users \ Pall \ Desktop \ proj1 \ lines.exe＆＃34; -g3 -I＆＃34; C：\ Program Files（x86）\ Dev-Cpp \ MinGW64 \ include＆＃34; -I＆＃34; C：\ Program Files（x86）\ Dev-Cpp \ MinGW64 \ x86_64-w64-mingw32 \ include＆＃34; -I＆＃34; C：\ Program Files（x86）\ Dev-Cpp \ MinGW64 \ lib \ gcc \ x86_64-w64-mingw32 \ 4.8.1 \ include＆＃34; -I＆＃34; C：\ Program Files（x86）\ Dev-Cpp \ MinGW64 \ lib \ gcc \ x86_64-w64-mingw32 \ 4.8.1 \ include \ c ++＆＃34; -L＆＃34; C：\ Program Files（x86）\ Dev-Cpp \ MinGW64 \ lib＆＃34; -L＆＃34; C：\ Program Files（x86）\ Dev-Cpp \ MinGW64 \ x86_64-w64-mingw32 \ lib＆＃34; -static-libgcc -g3   C：\ Users \ Pall \ AppData \ Local \ Temp \ ccRYW3Cy.o：在函数DrawLine(int, int, int, int, HPEN__*)': C:/Users/Pall/Desktop/proj1/lines.cpp:12: undefined reference to __ imp_SelectObject＆＃39;   C：/Users/Pall/Desktop/proj1/lines.cpp：13：对__imp_MoveToEx' C:/Users/Pall/Desktop/proj1/lines.cpp:14: undefined reference to __ imp_LineTo＆＃39;的未定义引用   C：\ Users \ Pall \ AppData \ Local \ Temp \ ccRYW3Cy.o：在函数WndProc(HWND__*, unsigned int, unsigned long long, long long)': C:/Users/Pall/Desktop/proj1/lines.cpp:36: undefined reference to __ imp_CreatePen＆＃39;   collect2.exe：错误：ld返回1退出状态

Answer 1

这是因为您需要链接库libgdi32.a，如果您使用的是DevC ++，请单击工具 - ＆gt;编译器选项，打开窗口时，选中框＆＃34;将这些命令添加到链接器命令行＆＃34;并在下面的文本框中添加文字：

-lgdi32

你需要像这样：

enter image description here

在关闭源代码然后再次打开它之后，我的c ++程序不会编译

1 个答案: