Fill the data...
  in main: sizeof(data) = 40 (10 ints)
  inside fill: sizeof(data) = 8 (the size of a pointer)
The data has been filled.
Show the data...
1 2 3 4 5 6 7 8 9 10 
sum of all ten = 55
sum of data[2..4] = 12
std::array sum = 26, std::vector sum = 10
