出现这些编译错误是为什么？

出现这些编译错误是为什么？ [所有相关帖子]

 
DibDoc.obj : error LNK2005: \"void * m_hDIB\" (?m_hDIB@@3PAXA) already defined in Dib.obj
DibDoc.obj : error LNK2005: \"class CPalette * m_palDIB\" (?m_palDIB@@3PAVCPalette@@A) already defined in Dib.obj
DibDoc.obj : error LNK2005: \"class CSize m_sizeDoc\" (?m_sizeDoc@@3VCSize@@A) already defined in Dib.obj
DibView.obj : error LNK2005: \"void * m_hDIB\" (?m_hDIB@@3PAXA) already defined in Dib.obj
DibView.obj : error LNK2005: \"class CPalette * m_palDIB\" (?m_palDIB@@3PAVCPalette@@A) already defined in Dib.obj
DibView.obj : error LNK2005: \"class CSize m_sizeDoc\" (?m_sizeDoc@@3VCSize@@A) already defined in Dib.obj
Debug/Dib.exe : fatal error LNK1169: one or more multiply defined symbols found
Error executing link.exe.