Template Error in c++

Question

#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;
    }

i am getting errors in lines with comments(specified the error).

Thank you for the complete program. It helps in diagnosing your problem. But, you have omitted one key element: a question. What is your question? — Robᵩ, Sep 11 '11 at 10:04
I am getting tons of errors (even after fixing commented lines) — BЈовић, Sep 11 '11 at 11:00

score 5 · Answer 1 · answered Sep 11 '11 at 10:02

5

Change your function definitions to

template<class T> Polynomial<T>::Polynomial(int size) { /* impl */ }

etc. (note the additional <T> after Polynomial).

answered Sep 11 '11 at 10:02

quant_dev

6,181
1
34
57

And after fixing that, decide whether `term` is a class or a struct, and add a `;` after the `class Polynomial`'s declaration... – Eran Sep 11 '11 at 10:07

score -1 · Answer 2 · answered Sep 11 '11 at 10:04

-1

You need to replace

Polynomial& Add(Polynomial b);
Polynomial& Mul(Polynomial b);

by

Polynomial<T>& Add(Polynomial<T> b);
Polynomial<T>& Mul(Polynomial<T> b);

(BTW, do you really want to pass your arguments a and b by value?). There are other places too where you use Polynomial without template arguments.

answered Sep 11 '11 at 10:04

amit kumar

20,438
23
90
126

2

This isn't true. There's a notion in C++ called injected class name. Look it up. The template arguments are needed in the function definitoins though – Armen Tsirunyan Sep 11 '11 at 10:09
1

Also, in the function definitions, you are allowed not to write the template arguments for the parameters. – Alexandre C. Sep 11 '11 at 10:12
@Alexandre: Yes, because the parameters in member function definition are already in class scope – Armen Tsirunyan Sep 11 '11 at 10:16
@Armen Thanks, I didn't know about injected class name. – amit kumar Sep 11 '11 at 10:36

Template Error in c++

2 Answers2