019. associate creates an alias for expressions or variables

topic: Associate

assoc.f90 | | |

integer, allocatable :: u(:)

u = [4,9]

associate (v => u)
v = v - 2
print *, v  ! 2 7
print *, u  ! 2 7

associate (w => [4, 9])
print *, w

! The following is illegal since `w` is set to a constant expression;
! it will raise a compilation error:
! w = w - 2  

! Need one for each of the `associate`s above
end associate
end associate

end

Output1

           2           7
           2           7
           4           9

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Associate creates an alias for expressions or variables.

integer, allocatable :: u(:)
u = [4,9]
associate (v => u)
v = v - 2
print*,v ! 2 7
print*,u ! 2 7
associate (w => [4,9])
print*,w
w = w - 2 ! illegal since w set to a constant expression
end associate
end associate
end

— FortranTip (@fortrantip) December 19, 2021

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Compiled using GNU Fortran (Ubuntu 11.3.0-1ubuntu1~22.04) 11.3.0 with no flags