(Solved) Why can templates only be implemented in the header file?

Caveat: It is not necessary to put the implementation in the header file, see the alternative solution at the end of this answer. Anyway, the reason your code is failing is that, when instantiating a template, the compiler creates a new class with the given template argument. For example: template<typename T> struct Foo { T … Read more

(Solved) Why is “using namespace std;” considered bad practice?

Introduction Using the “using namespace std;” statement in C++ is a controversial topic among developers. While it can be a convenient way to access the standard library, it can also lead to confusion and errors. In this article, we will discuss why using namespace std; is considered bad practice and what alternatives are available. We … Read more

(Solved) What is an undefined reference/unresolved external symbol error and how do I fix it?

Compiling a C++ program takes place in several steps, as specified by 2.2 (credits to Keith Thompson for the reference): The precedence among the syntax rules of translation is specified by the following phases [see footnote]. Physical source file characters are mapped, in an implementation-defined manner, to the basic source character set (introducing new-line characters … Read more