So, you have a message. I'll break the message in several lines. The message should be read like this:
LNK2019: unresolved external symbol
"some function or variable that compiler saw nicely declared but the linker can't find the definition of"
(name of the missing symbol as linker sees it)
referenced in function
"some function where the missing function/variable is being used"
(name of the function as linker sees it)
In your case linker needs function DoubleList::AccessActual(void)
in namespace SemestralWork
. The function is declared somewhere, most likely in DoubleList.h. You probably need to add DoubleList.cpp file to the project. Maybe you forgot to define the function? In that case you have to write it.
Also, you really, really need to remove using namespace
lines from header files. Really! Classes that exist in namespaces MUST be declared like this:
namespace SomeNamespace {
class SomeClass
{
void SomeFunction();
...
}
}
And SHOULD be defined like this in source file:
void SomeNamespace::SomeClass::SomeFunction()
{
...
}
In header files all stuff from any other namespaces, including std
namespace, SHOULD be used with full name (std::string
). In source files you MAY use using namespace std
AFTER all #include
directives. Some people disagree on this last one, but it's a matter of style.