Re: Simple program to find average of 3 numbers

[Preben Randhol <randhol+abuse@pvv.org>]

Stuart Palin wrote:
> "Robert I. Eachus" wrote:
>> 
>> prashna wrote:
>>  > Hi friends,
>>  >
>>  > What is wrong in the following program which is giving constraint
>>  > error?
>>  >
>>  > procedure average is type ONE_TO_100 is range 1 .. 100;
>>  >
>>  > OBJ1, OBJ2, OBJ3, AVG  : ONE_TO_100; begin OBJ1 := 70; OBJ2 := 70;
>>  > OBJ3 := 70; AVG := OBJ1+OBJ2+OBJ3/3; end average;
>> 
><snip>
>> 
>> Oh, and then I could talk about your formatting, and identifier style.
>> But I will address those by example.  Try:
>> 
>> procedure Average is
>>    subtype One_to_100 is Integer range 1 .. 100;
>>    Obj_1, Obj_2, Obj_3: One_to_100 := 70;
>>    Avg: One_to_100;
>> begin
>>    Avg := (Obj_1+Obj_2+Obj_3)/3;
>>    -- I assume you really wanted the average, rather than 163.
>> end Average;
> 
> You might also want to consider what values the intermediate
> calculation Obj_1+Obj_2+Obj_3 can take.  In this instance
> because your type is constrained to a number which should be
> well within the bounds of integer you would not experience a
> problem.

Which instance are you refering to? Mr Eachus' subtype or OP's type
declaration? If you do the calculations above aren't the
intermediate variable of the same type (ONE_TO_100) with same contraint
unless you use a subtype to Integer like Mr Eachus?

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