Thread: Why the example C++ code in MSDN is wrong?

I copied the exact code from MSDN here http://msdn.microsoft.com/en-us/library/f1b2td24.aspx

Code:

// template_friend1.cpp
// compile with: /EHsc

#include <iostream>
using namespace std;

template <class T> class Array {
   T* array;
   int size;

public:
   Array(int sz): size(sz) {
      array = new T[size];
      memset(array, 0, size * sizeof(T));
   }

   Array(const Array& a) {
      size = a.size;
      array = new T[size];
      memcpy_s(array, a.array, sizeof(T));
   }

   T& operator[](int i) {
      return *(array + i);
   }

   int Length() { return size; }

   void print() {
      for (int i = 0; i < size; i++)      
         cout << *(array + i) << " ";

      cout << endl;
   }

   template<class T>
   friend Array<T>* combine(Array<T>& a1, Array<T>& a2);
};

template<class T>
Array<T>* combine(Array<T>& a1, Array<T>& a2) {
   Array<T>* a = new Array<T>(a1.size + a2.size);
   for (int i = 0; i < a1.size; i++)
      (*a)[i] = *(a1.array + i);

   for (int i = 0; i < a2.size; i++)
      (*a)[i + a1.size] = *(a2.array + i);

   return a;
}

int main() {
   Array<char> alpha1(26);
   for (int i = 0 ; i < alpha1.Length() ; i++)
      alpha1[i] = 'A' + i;

   alpha1.print();

   Array<char> alpha2(26);
   for (int i = 0 ; i < alpha2.Length() ; i++)
      alpha2[i] = 'a' + i;

   alpha2.print();
   Array<char>*alpha3 = combine(alpha1, alpha2);
   alpha3->print();
   delete alpha3;
}

Why the complier complains :

g++ -c -g main.cc -o main.o
main.cc:33: error: declaration of `class T'
main.cc:4: error: shadows template parm `class T'
make: *** [main.o] Error 1

Anything wrong?

Originally Posted by cpjust

The MSDN isn't really known for their high quality code.

I agree here. That code is utterly, horrible, crap. *(array + i)? Isn't that exactly what array[i] is for? Also, don't use this with a class as type. The memset will completely ruin every class. Great job microsoft, once again...
Beats me what the memset is all about anyway.

Also, using Visual C++ it compiles and runs.
So the source is correct within the context it is supplied for.