IF statements and comparing character strings

Samohtvii · Aug 3, 2012

I have tried everything to get a simple bit of code to work but nothing has worked.
pseudocode:
get user answer (yes/no)
if answer = yes
print yes

I always get the same error "Cannot assign to a named constant"
i have tried
--
t = LGT(answer, 'yes')
IF(t)
--
if(answer .eq. 'yes)
--
if(LGT(answer, yes))
--
and any other combination.

Please help
Thanks

salgerman · Aug 3, 2012

please post the entire code

mazkime · Aug 3, 2012

Comparisons in 'if' statements are made with '==', because '=' is used for assignments. Moreover, when comparing characters, the characters you are comparing to need to be given between quotes ('').

The following example works with my computer (gfortran) :

Code:

  program main
  implicit none
  character*3 :: answer

  answer = 'yes'

  if (answer == 'yes') then
    print*,'test successful'
  endif

  end program main

Hope it helps.

mikrom · Aug 3, 2012

This works too

Code:

if (answer .eq. 'yes') then
...

Samohtvii · Aug 4, 2012

Got it. Thanks guys.

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IF statements and comparing character strings

Samohtvii

Programmer

salgerman

Programmer

mazkime

Technical User

mikrom

Programmer

Samohtvii

Programmer

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