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Fortran / Control Flow

If then else

Learn If then else in Fortran through a focused explanation, a dedicated topic-specific example, an engineering boundary, and a mastery check.

10 min read • Beginner

If then else is a focused Fortran lesson inside Control Flow. The example uses the construct named in the lesson directly rather than reusing a generic placeholder.

Trace the example from its inputs through If then else and identify the behavior that would change if that construct were removed or replaced. Pay attention to the language-specific rules shown by the syntax, because neighboring lessons intentionally exercise different mechanisms.

Topic-specific example

fortran-0021-dfa75185c5.f90
fortran Try It Live 
program demo
  implicit none
  integer :: values(3) = [22, 23, 24]
  print *, sum(values) ! If then else
end program demo
Edge case / engineering note

For If then else, test one realistic boundary: empty data, invalid input, unavailable resources, lifetime/cleanup, type constraints, or concurrency timing where applicable. A successful happy path is not enough to prove the construct is used correctly.

Content source & attribution
Original Syntaxis Content · Original Syntaxis Content

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