输出信息如下
1>main.obj : error LNK2019: 无法解析的外部符号 "public: __thiscall CDataConvertEngine<double>::CDataConvertEngine<double>(enum DataUnit)" (??0?$CDataConvertEngine@N@@QAE@W4DataUnit@@@Z),该符号在函数 _main 中被引用 1>main.obj : error LNK2001: 无法解析的外部符号 "public: virtual char const * __thiscall CDataConvertEngine<double>::toString(void)" (?toString@?$CDataConvertEngine@N@@UAEPBDXZ) 1>main.obj : error LNK2001: 无法解析的外部符号 "public: virtual double __thiscall CDataConvertEngine<double>::toDouble(void)" (?toDouble@?$CDataConvertEngine@N@@UAENXZ) 1>main.obj : error LNK2001: 无法解析的外部符号 "public: virtual int __thiscall CDataConvertEngine<double>::toInt(void)" (?toInt@?$CDataConvertEngine@N@@UAEHXZ) 1>main.obj : error LNK2001: 无法解析的外部符号 "public: virtual double __thiscall CDataConvertEngine<double>::to_pm(double)" (?to_pm@?$CDataConvertEngine@N@@UAENN@Z) 1>main.obj : error LNK2001: 无法解析的外部符号 "public: virtual double __thiscall CDataConvertEngine<double>::to_nm(double)" (?to_nm@?$CDataConvertEngine@N@@UAENN@Z) 1>main.obj : error LNK2001: 无法解析的外部符号 "public: virtual double __thiscall CDataConvertEngine<double>::to_um(double)" (?to_um@?$CDataConvertEngine@N@@UAENN@Z) 1>main.obj : error LNK2001: 无法解析的外部符号 "public: virtual double __thiscall CDataConvertEngine<double>::to_mm(double)" (?to_mm@?$CDataConvertEngine@N@@UAENN@Z) 1>main.obj : error LNK2001: 无法解析的外部符号 "public: virtual double __thiscall CDataConvertEngine<double>::to_cm(double)" (?to_cm@?$CDataConvertEngine@N@@UAENN@Z) 1>main.obj : error LNK2001: 无法解析的外部符号 "public: virtual double __thiscall CDataConvertEngine<double>::to_dm(double)" (?to_dm@?$CDataConvertEngine@N@@UAENN@Z) 1>main.obj : error LNK2001: 无法解析的外部符号 "public: virtual double __thiscall CDataConvertEngine<double>::to_m(double)" (?to_m@?$CDataConvertEngine@N@@UAENN@Z) 1>main.obj : error LNK2001: 无法解析的外部符号 "public: virtual double __thiscall CDataConvertEngine<double>::to_km(double)" (?to_km@?$CDataConvertEngine@N@@UAENN@Z) 1>main.obj : error LNK2001: 无法解析的外部符号 "public: virtual double __thiscall CDataConvertEngine<double>::to_deg(double)" (?to_deg@?$CDataConvertEngine@N@@UAENN@Z) 1>main.obj : error LNK2001: 无法解析的外部符号 "public: virtual double __thiscall CDataConvertEngine<double>::to_mdeg(double)" (?to_mdeg@?$CDataConvertEngine@N@@UAENN@Z) 1>main.obj : error LNK2001: 无法解析的外部符号 "public: virtual double __thiscall CDataConvertEngine<double>::to_rad(double)" (?to_rad@?$CDataConvertEngine@N@@UAENN@Z) 1>main.obj : error LNK2001: 无法解析的外部符号 "public: virtual double __thiscall CDataConvertEngine<double>::to_pls(double)" (?to_pls@?$CDataConvertEngine@N@@UAENN@Z) 1>main.obj : error LNK2001: 无法解析的外部符号 "public: virtual double __thiscall CDataConvertEngine<double>::to_mps(double,double)" (?to_mps@?$CDataConvertEngine@N@@UAENNN@Z) 1>main.obj : error LNK2001: 无法解析的外部符号 "public: virtual double __thiscall CDataConvertEngine<double>::to_mmps(double,double)" (?to_mmps@?$CDataConvertEngine@N@@UAENNN@Z) 1>main.obj : error LNK2001: 无法解析的外部符号 "public: virtual double __thiscall CDataConvertEngine<double>::to_mmpm(double,double)" (?to_mmpm@?$CDataConvertEngine@N@@UAENNN@Z) 1>main.obj : error LNK2001: 无法解析的外部符号 "public: virtual double __thiscall CDataConvertEngine<double>::to_rpm(double,double)" (?to_rpm@?$CDataConvertEngine@N@@UAENNN@Z) 1>main.obj : error LNK2001: 无法解析的外部符号 "public: virtual double __thiscall CDataConvertEngine<double>::to_radps(double,double)" (?to_radps@?$CDataConvertEngine@N@@UAENNN@Z) 1>main.obj : error LNK2001: 无法解析的外部符号 "public: virtual double __thiscall CDataConvertEngine<double>::to_radpm(double,double)" (?to_radpm@?$CDataConvertEngine@N@@UAENNN@Z) 1>main.obj : error LNK2001: 无法解析的外部符号 "public: virtual double __thiscall CDataConvertEngine<double>::to_pltpt(double,double)" (?to_pltpt@?$CDataConvertEngine@N@@UAENNN@Z)