C++ 中的模板错误

#include<iostream>
using namespace std;
template<class T>
struct term
{
          T coef;
          int exp;

};
template<class T>
class Polynomial
{
 public:
   class term<T> *termarray;
   int capacity;
   int terms;
   Polynomial(int size);
   ~Polynomial()
   {
       delete[] termarray;
   }
   Polynomial& Add(Polynomial b);
   Polynomial& Mul(Polynomial b);
   void NewTerm(const float theCoef,const int theExp);
   void show();
   };
template<class T>
   Polynomial::Polynomial(int size)// Invalid use of template-name'Polynomial'without argument list
  {
   terms=0;
   this->termarray=new T [size];
   capacity=size;
   for(int i=0;i<size;i++)
{
    cout<<"enter the coefficient of the "<<i<<"th exponent coeffecient"<<endl;
    cin>>this->termarray[i].coef;
    terms++;
}
}
template<class T>//expected unqualified-id before template
void Polynomial::NewTerm(const float theCoef, const int theExp)
{
    if(terms==capacity)
   {
        capacity=capacity*2;
    term *temp=new term[capacity];
    copy(termarray,termarray+terms,temp);
    delete[]termarray;
    termarray=temp;
}
termarray[terms].coef=theCoef;
termarray[terms++].exp=theExp;
}
template<class T>
Polynomial& Polynomial::Add(Polynomial b)//invalid use of template-name 'Polynomial'without an argument list
{
Polynomial c;
int aPos=0,bPos=0;
while((aPos<terms)&&(bPos<b.terms))
{
    if(termarray[aPos].exp==b.terarray[bPos].exp){
        float t=termarray[aPos].coef+b.termarray[bPos].exp;
        if(t) c.NewTerm(t,termarray[aPos].exp);
    }
}
else if((termarray[aPos].exp<b.termarray[bPos].exp))
  {
  c.NewTerm(b.termarray[bPos].coef,b.termarray[bPos].exp);
     bPos++;
     }
     else
  {
          c.NewTerm(termarray[aPos].coef,termarray[aPos].exp);
          aPos++;
       }
  for(;aPos<terms;Pos++)
  {
     c.NewTerm(termarray[aPos].coef,termarray[aPos].exp);
   }
   for(;bPos<b.terms;b++)
        c.NewTerm(b.termarray[bPos].coef,b.termarray[bPos].exp);
   return c;
  }
template<class T>// expected unqualified-id before 'template'
void Polynomial::show()
{
 int aPos=0;bPos=0;
    for(int i=0;i<terms;i++)
        cout<<this->termarray[i].coef<<this->termarray[i].exp;
           if(i<terms-1)
 {
           cout<<"+";
}
}   
int main()
{
    Polynomial<int> fx(2);
    Polynomial<int> fy(2);
    Polynomial<int> c(2);
    c= fx.Add(fy);
    c.show();
    return 0;
    }

我在带有注释的行中收到错误(指定错误(。