Using arrays and templates in c++ - c++

Question

in an attempt to understand templates better (and thus be able to read basic documentation on c++), I am trying to perform basic operations on arrays as templates. Below is code that defines a function template for averaging an array:
#include <iostream>
#include <array>
using namespace std;
template<class T>
double GetAverage(T tArray[])
{
T tSum = T(); // tSum = 0
int n=tArray.size();
for (int nIndex = 0; nIndex < n; ++nIndex)
{
tSum += tArray[nIndex];
}
// Whatever type of T is, convert to double
return double(tSum) / n;
}
int main ()
{
array<int,5> data={0,1,2,3,4};
cout << GetAverage(data);
cin.get();
return 0;
}
For some reason, as you will see, the compiler runs into issues when dealing with properties of the array, such as array.size(), all within the defining code of a function. I get the following error:
error: no matching function for call to 'GetAverage'
cout << GetAverage(data);
^~~~~~~~~~
note: candidate template ignored: could not match 'T *' against 'array<int, 5>'
double GetAverage(T tArray[])
^
How can I refer to the properties of an object when defining a function which takes in said object as input (all the while using the language of templates)?

Answer 1

C++11 array is a STL container, not a C array thus the following is incorrect:
T tArray[]
A correct version of the above could be
#include <iostream>
#include <array>
#include <numeric>
using namespace std;
template<class T>
double GetAverage(T tArray)
{
// More compact version as suggested by juanchopanza
auto avg = std::accumulate(begin(tArray), end(tArray), 0.0)/tArray.size();
return avg;
}
int main ()
{
array<int,5> data={0,1,2,3,4};
cout << GetAverage(data);
cin.get();
return 0;
}
http://ideone.com/RyPqOr
if you intend to use something more sophisticated you might have to use a struct or a class since functions don't have partial specialization.