Fortran Fortran 90 creating an array of unknown size

[max2112]

I was given an assignment to create a program that solves the Josephus Problem (.[/PLAIN] the program needs to work for n amount of people, and it must use an array.

Problem:
I need to create a subroutine that will allow the user to read(*,*) n
and create an array that is n big.

Attempt:

subroutine sub(n)
implicit none
integer :: n, i
integer :: array(n)
do i = 1, n
array(i) = 0
end do
end subroutine sub

program arrays
implicit none

integer :: size, i
write(*,*) "how big is your array"
read(*,*) size
call sub(size)



end program arrays

I am stuck, and don't know why this isn't working.

 

[Mark44]

I was given an assignment to create a program that solves the Josephus Problem (.[/PLAIN] the program needs to work for n amount of people, and it must use an array.

Problem:
I need to create a subroutine that will allow the user to read(*,*) n
and create an array that is n big.

Attempt:
Mod note: I added [noparse]a

 tag at the top of your code, and a

tag at the bottom[/noparse]. You should do that when you post code as it makes your code easier to read, by preserving your indentation.[/color]

subroutine sub(n)
	implicit none
	integer :: n, i
	integer :: array(n)
	do i = 1, n
		array(i) = 0
	end do
end subroutine sub

program arrays
	implicit none

	integer :: size, i
  write(*,*) "how big is your array"
	read(*,*) size
	call sub(size)



end program arrays

I am stuck, and don't know why this isn't working.

Here's a link to an article about arrays in fortran 90 - http://orion.math.iastate.edu/burkardt/papers/fortran_arrays.html . Take a look at the whole article, but especially the section on dynamic arrays.

 

[billiards]

Summit like this:

subroutine(/arguments/)

real,allocatable :: array(:)

/code/

allocate ( array(x) )

/code/

deallocate ( array )

return

 

[Louisa]

I was given an assignment to create a program that solves the Josephus Problem (.[/PLAIN] the program needs to work for n amount of people, and it must use an array.

Problem:
I need to create a subroutine that will allow the user to read(*,*) n
and create an array that is n big.

Attempt:

subroutine sub(n)
implicit none
integer :: n, i
integer :: array(n)
do i = 1, n
array(i) = 0
end do
end subroutine sub

program arrays
implicit none

integer :: size, i
write(*,*) "how big is your array"
read(*,*) size
call sub(size)



end program arrays

I am stuck, and don't know why this isn't working.

Why do you think that is not working?
You didn't print out anything after the value of "n" is typed.