Pat wrote:
> Francis Glassborow wrote:
>> Pat wrote:
>>> I'm in the process of teaching myself C++ (with the help of several
>>> good books) so I can develop some DLL's for another application.
>>>
>>> Looking through an example of one of these, there's a line that
>>> defines a structure as follows:
>>>
>>> struct ParameterDefinition primaryParams[]=
>>> {
>>> {"x position =", kXpos, 1.0}
>>> {"y position =", kYpos, 2.0}
>>> {"z position =", kZpos, 0.0}
>>> };
>>>
>>>
>>> None of the books I've been reviewing define a structure in this way
>>> (at least so far). So what is "ParameterDefinition"? A pointer? I
>>> assume it actually contains the code that defines this structure
>>> type. Is there a name for this way defining a structure? I'd like
>>> to read more about that.
>>
>> No, you have misunderstood. The above is NOT a definition of a struct.
>> struct ParameterDefinition is a type written in C form, C++ would just
>> use ParameterDefinition (it does not need the prefix 'struct' to tell
>> the compiler that the following is the name of a struct type.
>>
>> Now given that 'struct ParameterDefinition' is just a long winded name
>> for a type we can read the whole declaration/definition as:
>>
>> primaryParams is an array (size to be deduced from the provided
>> initialisers) of type ParameterDefinition which is to be initialised
>> with three sets of values.
>>
>> Compare this with the simpler but similar
>>
>> int array[] = {1, 2, 3};
>
>
> Thanks. You're right. I removed the "struct" (so it just reads
> "ParameterDefinition primaryParams[]=") and it stilled compiled and ran
> fine. So that now makes sense (except now I'm going have to sort out
> what's C vs C++ !)
>
> The question now though is where is ParameterDefinition actually
> defined? It's definition is not shown in the source file I'm working
> with. I guess I need to start checking the files referenced in the
> headers.
>
> But as an academic exercise, I assume ParameterDefinition looks
> something like this?
>
> struct ParameterDefinition
> {
> char coordinateName[20];
> double units;
> double coordinateValue;
> };
>
Correct
>
>
> (BTW, there should have been commas after each structure element in my
> original example).
>
- Jensen
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