program switch_example
    implicit none
    integer :: i
    character(len=20) :: day

    ! Here’s a basic switch.
    i = 2
    print *, 'Write ', i, ' as '
    select case (i)
    case (1)
        print *, 'one'
    case (2)
        print *, 'two'
    case (3)
        print *, 'three'
    end select

    ! Using select case with derived values.
    day = weekday()
    select case (day)
    case ('Saturday', 'Sunday')
        print *, "It's the weekend"
    case default
        print *, "It's a weekday"
    end select

    ! Using select case without an expression.
    select case (.true.)
    case (hour() < 12)
        print *, "It's before noon"
    case default
        print *, "It's after noon"
    end select

    ! A type switch is not something Fortran does directly. 
    ! However, for demonstration, let's use a simple type check.
    call whatAmI(.true.)
    call whatAmI(1)
    call whatAmI('hey')

contains

    function weekday() result(day)
        character(len=20) :: day
        ! This is a placeholder function.
        ! A proper implementation would return the current day of the week.
        day = 'Monday'
    end function weekday

    function hour() result(h)
        integer :: h
        ! This is a placeholder function.
        ! A proper implementation would return the current hour.
        h = 13
    end function hour

    subroutine whatAmI(i)
        class(*), intent(in) :: i
        select type(i)
        type is( logical )
            print *, "I'm a bool"
        type is( integer )
            print *, "I'm an int"
        type is( character(len=*) )
            print *, "Don't know type ", 'string'
        end select
    end subroutine whatAmI

end program switch_example