Re: Please read this..thank you

["Howard W. LUDWIG" <howard.w.ludwig@lmco.com>]

Sho wrote:
> 
> Dear Ada Programmers,
> 
> Could you please help me with the algorithms on how to convert Infix to
> a Postfix expression? examples:
> 
> Infix: 1 + 2 + 3
> Postfix: 1 2 3 + +

I do not know whether you were simply trying to put together a quick, 
simple example without paying close attention to what you were doing 
(and consequently made a silly mistake) or you have an actual 
misunderstanding which may cause you troubles in trying to compose 
appropriate code.  However, your example is in error:

While we all know that addition of integers (and, more generally, real 
and complex numbers) is associative, so that (1 + 2) + 3 = 1 + (2 + 3).  
However, most applications (APL being the only major exception I know) 
regard 1 + 2 + 3 as meaning (1 + 2) + 3 (which might be modified by 
application of commutative and associative principles to some other 
arrangement--note that Ada is restrictive regarding such rearrangements 
for floating point values due to the "non-real" floating-point model, 
so I am not being pedantic here; another example would be an operation, 
such as subtraction, which is nonassociative).   Now,
   (1 + 2) + 3  is  1 2 + 3 +  in infix
whereas
   1 + (2 + 3)  is  1 2 3 + +  in infix.
 
> Sho

Howard W. LUDWIG
Working (but not speaking) for Lockheed Martin Electronics & Missiles
Co.