请问这是什么原因造成的错误，新手c++，在做一个图像处理的工程，求教

Question

1>DIPDemoView.obj : error LNK2019: unresolved external symbol "public: virtual __thiscall CDlgHuffman::~CDlgHuffman(void)" (??1CDlgHuffman@@UAE@XZ) referenced in function "public: void __thiscall CDIPDemoView::OnHuffman(void)" (?OnHuffman@CDIPDemoView@@QAEXXZ)

1>DIPDemoView.obj : error LNK2019: unresolved external symbol "public: __thiscall CDlgHuffman::CDlgHuffman(class CWnd *)" (??0CDlgHuffman@@QAE@PAVCWnd@@@Z) referenced in function "public: void __thiscall CDIPDemoView::OnHuffman(void)" (?OnHuffman@CDIPDemoView@@QAEXXZ)
1>DIPDemoView.obj : error LNK2019: unresolved external symbol "public: virtual __thiscall CDlgDCT::~CDlgDCT(void)" (??1CDlgDCT@@UAE@XZ) referenced in function "public: void __thiscall CDIPDemoView::OnMenuDct(void)" (?OnMenuDct@CDIPDemoView@@QAEXXZ)

1>DIPDemoView.obj : error LNK2019: unresolved external symbol "public: __thiscall CDlgDCT::CDlgDCT(class CWnd *)" (??0CDlgDCT@@QAE@PAVCWnd@@@Z) referenced in function "public: void __thiscall CDIPDemoView::OnMenuDct(void)" (?OnMenuDct@CDIPDemoView@@QAEXXZ)

1>DIPDemoView.obj : error LNK2019: unresolved external symbol "public: virtual __thiscall CDlgArith::~CDlgArith(void)" (??1CDlgArith@@UAE@XZ) referenced in function "public: void __thiscall CDIPDemoView::OnMuneArith(void)" (?OnMuneArith@CDIPDemoView@@QAEXXZ)

1>DIPDemoView.obj : error LNK2019: unresolved external symbol "public: __thiscall CDlgArith::CDlgArith(class CWnd *)" (??0CDlgArith@@QAE@PAVCWnd@@@Z) referenced in function "public: void __thiscall CDIPDemoView::OnMuneArith(void)" (?OnMuneArith@CDIPDemoView@@QAEXXZ)

1>DIPDemoView.obj : error LNK2019: unresolved external symbol "public: virtual __thiscall CDlgInvFilter::~CDlgInvFilter(void)" (??1CDlgInvFilter@@UAE@XZ) referenced in function "public: void __thiscall CDIPDemoView::OnInvRestore(void)" (?OnInvRestore@CDIPDemoView@@QAEXXZ)

1>DIPDemoView.obj : error LNK2019: unresolved external symbol "public: __thiscall CDlgInvFilter::CDlgInvFilter(class CWnd *)" (??0CDlgInvFilter@@QAE@PAVCWnd@@@Z) referenced in function "public: void __thiscall CDIPDemoView::OnInvRestore(void)" (?OnInvRestore@CDIPDemoView@@QAEXXZ)

Answer 1

如果代码不是你写的，并且确信以前是好的，那么可能是头文件或者lib文件没有引用对路径，在项目-属性-目录中看看