What Does the Fortran Statement 'IF ( IP - I1 ) 180, 170, 180' Mean?

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SUMMARY

The Fortran statement 'IF ( IP - I1 ) 180, 170, 180' is an example of an "arithmetic IF" statement. It directs the program's flow based on the result of the expression 'IP - I1'. Specifically, if 'IP - I1' is less than zero, the program jumps to statement 180; if it equals zero, it jumps to statement 170; and if it is greater than zero, it again jumps to statement 180. This construct is characteristic of older Fortran code, reflecting its historical usage in programming.

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agalya
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Hi all,

What is the meaning of the following Fortran statement

IF ( IP - I1 ) 180, 170, 180

kindly help,
thank u,
 
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This is an "arithmetic IF" statement.

If IP - I1 < 0, go to statement 180.
If IP - I1 = 0, go to statement 170.
If IP - I1 > 0, go to statement 180.

You must be reading very old code. :smile:
 

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