program arrays
    implicit none
    integer :: i, j
    integer :: a(5)
    integer :: b(5)
    integer :: twoD(2,3)

    ! Here we create an array 'a' that will hold exactly 5 integers.
    ! By default, an array is zero-valued in Fortran.
    print *, "emp:", a

    ! We can set a value at an index using the array(index) = value syntax,
    ! and get a value with array(index).
    a(5) = 100
    print *, "set:", a
    print *, "get:", a(5)

    ! The intrinsic function 'size' returns the length of an array.
    print *, "len:", size(a)

    ! Use this syntax to declare and initialize an array in one line.
    b = [1, 2, 3, 4, 5]
    print *, "dcl:", b

    ! In Fortran, you can't have the compiler count the number of elements for you.
    ! You need to explicitly specify the size or use dynamic allocation.

    ! If you want to initialize only specific elements, you can use this syntax:
    b = [100, 0, 0, 400, 500]
    print *, "idx:", b

    ! Array types are multi-dimensional by default in Fortran.
    ! Here's how to create and initialize a 2D array:
    do i = 1, 2
        do j = 1, 3
            twoD(i,j) = i + j - 2
        end do
    end do
    print *, "2d: ", twoD

    ! You can create and initialize multi-dimensional arrays at once too.
    twoD = reshape([1, 2, 3, 1, 2, 3], [2, 3])
    print *, "2d: ", twoD

end program arrays