Question

Consider:

#include <iostream>

template <typename T> T getArray( T &arr ) {
    return *arr;
}

int main() {

    int a[] = {5, 3, 6};

    std::cout << getArray(a);

}

It’s suppose to print the first element in the array but it is not not working. Why is that?

It gives me the error:

error: no matching function for call to 'getArray(int [3])'

Answer 1

The type of a is int[3], so the type of T is int[3]. Arrays cannot be returned from functions.

In C++11, you can do this:

template <typename T>
auto getArray(T &arr) -> decltype(*arr)
{ 
    return *arr; 
} 

Or this:

// requires <type_traits>

template <typename T>
typename std::remove_extent<T>::type& getArray(T &arr)
{ 
    return *arr; 
} 

In C++03 you can do this, but it’s not quite the same:

template <typename T>
T getArray(T* arr /* not really an array */)
{ 
    return *arr; 
} 

Or:

template <typename T, std::size_t N>
T getArray(T (&arr)[N])
{ 
    return *arr; 
}