Non-inline function definitions

Of course, there are times when you’ll want to have non-inline member function definitions. In this case, the compiler needs to see the template declaration before the member function definition. Here’s the example above, modified to show the non-inline member definition:

//: C16:Array2.cpp

// Non-inline template definition

#include "../require.h"

template<class T>

class Array {

  enum { size = 100 };

  T A[size];

public:

  T& operator[](int index);

};

template<class T>

T& Array<T>::operator[](int index) {

  require(index >= 0 && index < size,

    "Index out of range");

  return A[index];

}

int main() {

  Array<float> fa;

  fa[0] = 1.414;

} ///:~

Any reference to a template’s class name must be accompanied by its template argument list, as in Array<T>::operator[]. You can imagine that internally, the class name is being decorated with the arguments in the template argument list to produce a unique class name identifier for each template instantiation.