Help with a double "IF" statement

[aclark-3]

Hello.

I'm having trouble combining 2 "IF" statements. I'm sure this is a piece of cake for you experts.

Here is the general form of my program (the actual equations are more complicated).

X=A   If  M=1

X=B   If M=2  and If N=1

X=C  If M=2 and If N=0  (or simply X=C  otherwise)

Thanks, Al Clark

[TomU]

You're posting this in the general community help section - meaning help with the community site itself, not some specific PTC software.  If you can tell us what software you're using, we can provide a better response.

[MartinHanak]

Hi,

in case that you need to define model relations, please see following code.

/* M, N are integer values

X=C

if M==1

  X=A

endif

if M==2

  if N==1

    X=B

  endif

endif

MH

[RichardJ]

Since you have posted in the Mathcad forums before I assume this is a Mathcad question, in which case the best solution is a small program:

Note that you cannot just type "return", "if" and "otherwise". They must be entered from the programming toolbar.

Toby Metcalf‌ please move this to the Mathcad forums.

[Tmetcalf]

Thanks Richard

[AlvaroDíaz]

Hi Richard

Some purist can say that returns isn't a proper instruction for structured languages. And I'm a strong advocate of GoTo, GoSub and those instructions, but mathcad have a particular implementation for a sequence of if statements.

Best regards.

Alvaro.

[RichardJ]

If Mathcad programs were better structured (and in Prime they actually are; one of the few benefits of Prime) I would agree. However, as you note even a dead string used as a comment, such as "some stuff", in the middle of the if statement breaks the logic. So I make a habit of using a return statement if I explicitly want the program to exit and return a specific value at that point. I agree it's not ideal, but I didn't design Mathcad programming

[AlvaroDíaz]

Richard Jackson wrote:

... but I didn't design Mathcad programming

Unfortunate for  us.  I'm pretty sure that you can improve a lot of things and implement very good news routines.

Best regards.

Alvaro

[RichardJ]

Well, Prime does not suffer from this problem with unexpected results from if statements that are broken by comments. I'm proud to say that's at least partly because I made an issue out of it

[AlvaroDíaz]

Second and subsequent if's are actually elseif but assumed by the context not by a keyword which could be the better option : a ben program command with a well defined logic

[RichardJ]

Agreed. That's what is in Prime. It has both "else if" and "also if". That makes it very clear what the intent is.

[-MFra-]

Hi

Even so, it would be fine, do not you think?

[aclark-3]

Thanks everyone for your help. I didn't realize that I would initiate such a discussion.

Actually all I needed was to be steered to the Boolean "and", and then I was all set.

Regards, Al