std::array<T,N>::begin, std::array<T,N>::cbegin

#include <algorithm>
#include <array>
#include <iomanip>
#include <iostream>
 
int main()
{
 std::cout << std::boolalpha ;
 
 std::array <int, 0> empty;
 std::cout << "1) "
 << (empty.begin() == empty.end()) << ' ' // true
 << (empty.cbegin() == empty.cend()) << '\n'; // true
 // *(empty.begin()) = 42; // => undefined behavior at run-time
 
 
 std::array <int, 4> numbers{5, 2, 3, 4};
 std::cout << "2) "
 << (numbers.begin() == numbers.end()) << ' ' // false
 << (numbers.cbegin() == numbers.cend()) << '\n' // false
 << "3) "
 << *(numbers.begin()) << ' ' // 5
 << *(numbers.cbegin()) << '\n'; // 5
 
 *numbers.begin() = 1;
 std::cout << "4) " << *(numbers.begin()) << '\n'; // 1
 // *(numbers.cbegin()) = 42; // compile-time error: 
 // read-only variable is not assignable
 
 // print out all elements
 std::cout << "5) ";
 std::for_each (numbers.cbegin(), numbers.cend(), [](int x)
 {
 std::cout << x << ' ';
 });
 std::cout << '\n';
 
 constexpr std::array constants{'A', 'B', 'C'};
 static_assert(constants.begin() != constants.end()); // OK
 static_assert(constants.cbegin() != constants.cend()); // OK
 static_assert(*constants.begin() == 'A'); // OK
 static_assert(*constants.cbegin() == 'A'); // OK
 // *constants.begin() = 'Z'; // compile-time error: 
 // read-only variable is not assignable
}

1) true true
2) false false
3) 5 5
4) 1
5) 1 2 3 4