Fortran Cheat Sheet

program hello    implicit none          ! always use this    integer :: i, j    real :: x, y    real(kind=8) :: z      ! double precision    character(len=20) :: name    logical :: flag    x = 3.14    name = 'Fortran'    print *, 'Hello, World!'    print *, 'x =', xend program hello

if (x > 0) then    print *, 'positive'else if (x < 0) then    print *, 'negative'else    print *, 'zero'end ifselect case (n)case (1)    print *, 'one'case (2:5)    print *, 'two to five'case default    print *, 'other'end selectdo i = 1, 10    print *, iend dodo while (x < 10.0)    x = x + 1.0end do

integer :: arr(10)integer, dimension(3,3) :: matrixreal, allocatable :: dyn(:)arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]arr(1:5) = 0             ! slice assignmentallocate(dyn(100))print *, sum(arr)        ! sum of all elementsprint *, size(arr)       ! number of elementsprint *, maxval(arr)     ! largest elementdeallocate(dyn)

module mymod    implicit nonecontains    function square(x) result(y)        real, intent(in) :: x        real :: y        y = x * x    end function square    subroutine greet(name)        character(len=*), intent(in) :: name        print *, 'Hello, ', name    end subroutine greetend module mymodprogram main    use mymod    implicit none    call greet('World')    print *, square(4.0)end program main