artyom@artyom-MSI:/tmp/aleksZubakov/build$ make
[ 50%] Linking CXX executable EmailServer
CMakeFiles/EmailServer.dir/src/main.cpp.o: In function `operations::Operation::Operation(operations::Type)':
main.cpp:(.text._ZN10operations9OperationC2ENS_4TypeE[_ZN10operations9OperationC5ENS_4TypeE]+0xe): undefined reference to `vtable for operations::Operation'
CMakeFiles/EmailServer.dir/src/main.cpp.o: In function `operations::Operation::~Operation()':
main.cpp:(.text._ZN10operations9OperationD2Ev[_ZN10operations9OperationD5Ev]+0xb): undefined reference to `vtable for operations::Operation'
CMakeFiles/EmailServer.dir/src/main.cpp.o:(.data.rel.ro._ZTVN10operations15BinaryOperationE[_ZTVN10operations15BinaryOperationE]+0x10): undefined reference to `operations::Operation::evaluate() const'
CMakeFiles/EmailServer.dir/src/main.cpp.o:(.data.rel.ro._ZTVN10operations14UnaryOperationE[_ZTVN10operations14UnaryOperationE]+0x10): undefined reference to `operations::Operation::evaluate() const'
CMakeFiles/EmailServer.dir/src/main.cpp.o:(.data.rel.ro._ZTIN10operations13LongOperationE[_ZTIN10operations13LongOperationE]+0x10): undefined reference to `typeinfo for operations::Operation'
CMakeFiles/EmailServer.dir/src/main.cpp.o:(.data.rel.ro._ZTIN10operations15BinaryOperationE[_ZTIN10operations15BinaryOperationE]+0x10): undefined reference to `typeinfo for operations::Operation'
CMakeFiles/EmailServer.dir/src/main.cpp.o:(.data.rel.ro._ZTIN10operations14UnaryOperationE[_ZTIN10operations14UnaryOperationE]+0x10): undefined reference to `typeinfo for operations::Operation'
collect2: error: ld returned 1 exit status
CalculatorServer/CMakeFiles/EmailServer.dir/build.make:94: recipe for target 'CalculatorServer/EmailServer' failed
make[2]: *** [CalculatorServer/EmailServer] Error 1
CMakeFiles/Makefile2:85: recipe for target 'CalculatorServer/CMakeFiles/EmailServer.dir/all' failed
make[1]: *** [CalculatorServer/CMakeFiles/EmailServer.dir/all] Error 2
Makefile:83: recipe for target 'all' failed
make: *** [all] Error 2