Template issue

[Vespasian]

I create an templated Array class. My constructor declaration is as
follows,
template<class X> Array<X>::Array (int s); // Constructor

I also have templated sorting function,
template<class X> void Quicksort(X values[], int first, int last);

I am getting the following compilation error,

error C2784: 'void Quicksort(X [],int,int)' : could not deduce
template argument for 'T1 []' from 'Array<X>'
with
[
X=std::string
]

My dirver code,

// Read in an array of strings
cout << "How many words? ";
cin >> num;
Array<string> b(num);
cout << "Enter the " << num << " words below:\n";
for (int i=0; i<num ; i++) cin >> b[i];

// Copy the original array and sort it using Quicksort
Array<string> bq(b);
Quicksort(bq, 0, num-1);
cout << "\nElements sorted using quicksort:\n";
for (int i=0; i<num ; i++) cout << bq[i]<< " ";

Don't know what's wrong. Any help is appreciated,
TIA,
Ves

[John Harrison]

Re: Template issue


"Vespasian" <julie.spicer@v erizon.net> wrote in message
news:obeva0l4rr ptmsnqqburarf77 jqeiotgih@4ax.c om...[color=blue]
> I create an templated Array class. My constructor declaration is as
> follows,
> template<class X> Array<X>::Array (int s); // Constructor
>
> I also have templated sorting function,
> template<class X> void Quicksort(X values[], int first, int last);
>
> I am getting the following compilation error,
>
> error C2784: 'void Quicksort(X [],int,int)' : could not deduce
> template argument for 'T1 []' from 'Array<X>'
> with
> [
> X=std::string
> ][/color]

Simple enough, your Quicksort routine expects X[], you are giving it
Array<X>. They aren't the same.

john

[Vespasian]

Re: Template issue

On Sat, 22 May 2004 22:49:12 +0100, "John Harrison"
<john_andronicu s@hotmail.com> wrote:
[color=blue]
>
>"Vespasian" <julie.spicer@v erizon.net> wrote in message
>news:obeva0l4r rptmsnqqburarf7 7jqeiotgih@4ax. com...[color=green]
>> I create an templated Array class. My constructor declaration is as
>> follows,
>> template<class X> Array<X>::Array (int s); // Constructor
>>
>> I also have templated sorting function,
>> template<class X> void Quicksort(X values[], int first, int last);
>>
>> I am getting the following compilation error,
>>
>> error C2784: 'void Quicksort(X [],int,int)' : could not deduce
>> template argument for 'T1 []' from 'Array<X>'
>> with
>> [
>> X=std::string
>> ][/color]
>
>Simple enough, your Quicksort routine expects X[], you are giving it
>Array<X>. They aren't the same.
>
>john
>[/color]

I changes my declartation to and still get similiar error,

template<class X> void Quicksort(Array <X> values[], int first, int
last);

c:\Files\docume nts\dataStuctur es_HW\hw7\gener ic.cpp(55): error C2784:
'void Quicksort(Array <X> [],int,int)' : could not deduce template
argument for 'Array<X> []' from 'Array<X>'
with
[
X=std::string
]

[Jorge Rivera]

Re: Template issue

Vespasian wrote:[color=blue]
> On Sat, 22 May 2004 22:49:12 +0100, "John Harrison"
> <john_andronicu s@hotmail.com> wrote:
>
>[color=green]
>>"Vespasian" <julie.spicer@v erizon.net> wrote in message
>>news:obeva0l4 rrptmsnqqburarf 77jqeiotgih@4ax .com...
>>[color=darkred]
>>>I create an templated Array class. My constructor declaration is as
>>>follows,
>>>template<cla ss X> Array<X>::Array (int s); // Constructor
>>>
>>>I also have templated sorting function,
>>>template<cla ss X> void Quicksort(X values[], int first, int last);
>>>
>>>I am getting the following compilation error,
>>>
>>>error C2784: 'void Quicksort(X [],int,int)' : could not deduce
>>>template argument for 'T1 []' from 'Array<X>'
>>> with
>>> [
>>> X=std::string
>>> ][/color]
>>
>>Simple enough, your Quicksort routine expects X[], you are giving it
>>Array<X>. They aren't the same.
>>
>>john
>>[/color]
>
>
> I changes my declartation to and still get similiar error,
>
> template<class X> void Quicksort(Array <X> values[], int first, int
> last);
>[/color]

Should be

template<class X> void Quicksort(X values, int first, int last);

with X=Array<string>

JLR

[Sergiy Kanilo]

Re: Template issue


"Vespasian" <julie.spicer@v erizon.net> wrote in message
news:r5kva09n1b mji9j0lfe4pp679 uniicolul@4ax.c om...
[color=blue][color=green][color=darkred]
> >> I am getting the following compilation error,
> >>
> >> error C2784: 'void Quicksort(X [],int,int)' : could not deduce
> >> template argument for 'T1 []' from 'Array<X>'[/color][/color][/color]

[...]
[color=blue]
> I changes my declartation to and still get similiar error,
>
> template<class X> void Quicksort(Array <X> values[], int first, int
> last);[/color]

You can try

template<class X> void Quicksort(Array <X>& values, int first, int last)
{
....
}

or even

template<class X> void Quicksort(X& values, int first, int last)
{
....
}

I believe that both variants will work (of course if your implementation
of Quicksort is correct)

Cheers,
Serge

[Vespasian]

Re: Template issue

On Sat, 22 May 2004 18:35:34 -0400, "Sergiy Kanilo"
<skanilo@artann labs.com> wrote:
[color=blue]
>
>"Vespasian" <julie.spicer@v erizon.net> wrote in message
>news:r5kva09n1 bmji9j0lfe4pp67 9uniicolul@4ax. com...
>[color=green][color=darkred]
>> >> I am getting the following compilation error,
>> >>
>> >> error C2784: 'void Quicksort(X [],int,int)' : could not deduce
>> >> template argument for 'T1 []' from 'Array<X>'[/color][/color]
>
>[...]
>[color=green]
>> I changes my declartation to and still get similiar error,
>>
>> template<class X> void Quicksort(Array <X> values[], int first, int
>> last);[/color]
>
>You can try
>
>template<cla ss X> void Quicksort(Array <X>& values, int first, int last)
>{
>...
>}
>
>or even
>
>template<cla ss X> void Quicksort(X& values, int first, int last)
>{
>...
>}
>
>I believe that both variants will work (of course if your implementation
>of Quicksort is correct)
>
>Cheers,
>Serge
>[/color]


Thanks, Serge -- that worked