ld: symbol(s) not found for architecture x86_64 clang: error: linker command failed with exit code 1 (use -v to see invocation)

Question

I have to do a custom \"vector\" class in c++ as homework for my university but I\'m struggling with the templates.

I get this error after I change all the variables\'

Answer 1

You should add template in your friend declaration in class Vector.

template 
friend ostream& operator <<(ostream& out, Vector x);

template 
friend bool operator == (const Vector &lop, const Vector &rop);