# 012. Fortran has allocation-on-assignment topic: {ref}`allocation` Fortran has allocation on assignment, but you cannot use the `allocate` statement for an array that is already allocated. ```{literalinclude} ../../src/alloc-on-assign.f90 :language: fortran :caption: alloc-on-assign.f90 | |

``` ```{code-block} text :caption: Output[^gfortran-version] ``` [^gfortran-version]: Compiled using `GNU Fortran (Ubuntu 11.3.0-1ubuntu1~22.04) 11.3.0` with no flags ---

Fortran has allocation on assignment, but you cannot use the ALLOCATE statement for an array that is allocated

integer, allocatable :: v(:)
v = [4,9]
deallocate(v) ! necessary for line below to work
allocate (v,source=[4,9]) ! same as above
— FortranTip (@fortrantip) December 18, 2021