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Protoman · Guest

I've been looking at template metaprogramming. It seems really cool,
make the compiler do most of the work. I have very simple program that
uses TMP,it calculates the square of a number, but it doesn't seem to
work. Here it is:

#include <iostream>
#include <cstdlib>
using namespace std;

template<int n>
class Sqr
{
public:
static const int RET = n*n;
};

Sqr sqr;

int main()
{
cout << sqr<10>::RET << endl;
system ("PAUSE");
return 0;
}

By all the websites I've read, this should work absolutely fine. Could
you help me? And, if it's any help, I'm using Bloodshed's Dev-Cpp
v4.9.9.2 compiler.

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msalters · Guest

Protoman schreef:

Ulrich Eckhardt · Guest

Protoman wrote:

Markus Moll · Guest

Hi

Protoman wrote:

noahwoo · Guest

Maybe your idea can be expressed like this :
(Tested by gcc)
#include <iostream>
#include <cstdlib>
using namespace std;

template<int n>
class Sqr
{
public:
static const int RET = n*n;

};

// Sqr<10> sqr;

int main()
{
cout << Sqr<10>::RET << endl;
system ("PAUSE");
return 0;
}

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Anthony Williams · Guest

"Protoman" <Protoman2050 (AT) gmail (DOT) com> writes:

Andy · Guest

Greg · Guest

Protoman wrote:

Martin Bonner · Guest

Protoman wrote:

tony_in_da_uk@yahoo.co.uk · Guest

What you're trying to do isn't actually template metaprogramming in any
meaningful sense, as metaprogramming involves templates instantiating
themselves or other templates to implement an algorithm, but I'll
ignore that for now and help you get it working as presented.

Perhaps you should look at the compiler error messages? The simplest
way to get what you've done going is to change "sqr<10>::RET" to
"Sqr<10>::RET", and remove the "Sqr sqr;" line (you'd need Sqr<10>
sqr;" there to get the intended effect, but you don't need an instance
of the templated class in order to use a static member.

Cheers, Tony

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Sasko Mateski · Guest

On 12 Aug 2005 05:08:13 -0400, Protoman wrote:

Valery Aronov · Guest

Try this instead:

....
Sqr<10> sqr;

int main() {
cout << sqr.RET << endl;
system ("PAUSE");
return 0;
}

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Stefan Chrobot · Guest

U=BFytkownik Protoman napisa=B3:

Dan McLeran · Guest

You're declaring a variable of Sqr type with no template arguments.
Here is a solution that works for both MSVC6 and GCC 3.3.1:

#include <iostream>
#include <cstdlib>
using namespace std;

template<int n>
class Sqr
{
public:
typedef enum {RET = n*n} ResultType;

};

int main()
{
cout << Sqr<10>::RET << endl;
system ("PAUSE");
return 0;
}

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mlimber · Guest

-- Protoman wrote: