Re: Subtypes with Combined Ranges

[David Rasmussen <pinkfloydhomer@yahoo.com>]

Jacob Sparre Andersen wrote:
> David Rasmussen wrote:
> 
>> An Ada-excercise reads as follows:
>>
>> 6.1 Write a program to count the number of occurrences of each letter 
>> of the alphabet typed as input at the keyboard. Using a subtype of 
>> Character as the index subtype of an array is a sensible way to do this.
>>
>> My first thought was to do this:
>> subtype Alphabetical is Character range 'A'..'Z' | 'a'..'z';
> 
> 
> I think your problem is that you misunderstand the exercise. "The 
> alphabet" is just 'a' to 'z' and case insensitive. But since the 
> alphabet actually is 'a' to '�', and not just 'a' to 'z', the advise in 
> the exercise is inapropriate for other languages than English and Latin.
> 
> I would assume that the alphabet considered by the user is a subset of 
> the type Character, but include all elements of type Character 
> (converted to lower case) in the histogram, and not worry about which 
> elements to show until printing out the histogram.
> 
> Jacob

That is of course one way to do it. But I understood the word "subtype" 
in the excercise, in the Ada sense of the word. So I wanted to actually 
make a subtype, and then declare an array with this type as index type. 
I can do that with the lowercase letters, of course, as long as we're 
talking about English or Latin.

/David