Example

 The following example is valid for all source forms:

 Column:

 12345678...                                                            73
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 ! Define the user function MY_SIN

       DOUBLE PRECISION FUNCTION MY_SIN(X)
         MY_SIN = X - X**3/FACTOR(3) + X**5/FACTOR(5)                    &
      &          - X**7/FACTOR(7)
       CONTAINS
         INTEGER FUNCTION FACTOR(N)
          FACTOR = 1
          DO 10 I = N, 1, -1
   10     FACTOR = FACTOR * I
         END FUNCTION FACTOR
       END FUNCTION MY_SIN