template class specialization : template-id does not match any template declaration

I'm trying to use templates, but couldn't understand what is wrong with below code.

solve.h

#include "nlp.h"
#include "Ipopt_solve.h"

enum algo_type {IPOPT =1, SQP};

template<int ALG>
class solve
{
public:
    solve()
    {
    }
};

template<>
class solve<IPOPT>
{
public:
    solve(nlp*);

private:
    Ipopt_solve m_ipopt;

};

solve.cpp

template<>
solve<IPOPT>::solve(nlp* problem): m_ipopt(problem)
{
}

Ipopt_solve is a sub-class of an abstract class TNLP. Ipopt_solve is initialized with a reference to nlp class.

from main.cpp

nlp problem(&model);
solve<IPOPT> solution(&problem);

I'm getting the error like shown below.

error: template-id 'solve<>' for 'solve<1>::solve(nlp*)' does not match any template declaration solve::solve(nlp* problem): m_ipopt(problem)