Computer Science Canada

**template class**
Author:  JessT0 [ Mon Mar 15, 2004 9:21 pm ]
Post subject:  **template class**
Anyone know how to convert this to template ?please help
given:
code:

class pair{
{
public:
   pair(char x):c1(x),c2(x+1){}
   void increment(){c1++,c2++;}
  void print() const {cout << c1<< "\t" << c2;}
private:
  char c1,c2;
};


here what i did
code:

template<class TYPE>
class pair{
public:
   pair(TYPE x):c1(x),c2(x+1){}
   void increment(){c1++,c2++;}
   void print() const {cout << c1<< "\t" << c2;}
private:
   TYPE c1,c2;
};
int main()
{

return 0;
}


note: the program has to have 3 instantiation of this class with type char,int,double.Create a pair for each of these types, print them,increment them,and then reprint them.Thank for reading
Author:  wtd [ Mon Mar 15, 2004 10:23 pm ]
Post subject: 
code:
#include <iostream>

template <typename _t>
class pair
{
   private:
      _t first, second;
   public:
      pair(_t, _t);
      friend std::ostream& operator<<(std::ostream&, const pair<_t>&);
      void operator++();
      void operator++(int);
};

int main()
{
   pair<char>   p1('A', 'B');
   pair<int>    p2(1, 9);
   pair<double> p3(1.2, 2.5);

   std::cout << p1 << std::endl;
   std::cout << p2 << std::endl;
   std::cout << p3 << std::endl;

   p1++;
   p2++;
   p3++;

   std::cout << p1 << std::endl;
   std::cout << p2 << std::endl;
   std::cout << p3 << std::endl;

   return 0;
}

template <typename _t>
pair<_t>::pair(_t init_first, _t init_second)
: first(init_first), second(init_second)
{ }

template <typename <_t>
std::ostream& operator<<(std::ostream& out, const pair<_t>& p)
{
   return out << p.first << "\t" << p.second;
}

template <typename <_t>
void pair<_t>::operator++()
{
   first++;
   second++;
}

template <typename <_t>
void pair<_t>::operator++(int)
{
   first++;
   second++;
}
Author:  JessT0 [ Wed Mar 17, 2004 11:17 am ]
Post subject: 
Thank wtd

did you compile this program?i compiled it and it doesn't work...Sad ...
Author:  wtd [ Wed Mar 17, 2004 7:12 pm ]
Post subject: 
The following fixes the typos and other errors. Smile

code:
#include <iostream>

template <typename _t>
class pair
{
   private:
      _t first, second;
   public:
      pair(_t, _t);

      void operator++();
      void operator++(int);

      template <typename __t>
      friend std::ostream& operator<<(std::ostream&, const pair<__t>&);
};



int main()
{
   pair<char>   p1('A', 'B');
   pair<int>    p2(1, 9);
   pair<double> p3(1.2, 2.5);

   std::cout << p1 << std::endl;
   std::cout << p2 << std::endl;
   std::cout << p3 << std::endl;

   p1++;
   p2++;
   p3++;

   std::cout << p1 << std::endl;
   std::cout << p2 << std::endl;
   std::cout << p3 << std::endl;

   return 0;
}



template <typename _t>
pair<_t>::pair(_t init_first, _t init_second)
: first(init_first), second(init_second)
{ }

template <typename _t>
std::ostream& operator<<(std::ostream& out, const pair<_t>& p)
{
   return out << p.first << "\t" << p.second;
}

template <typename _t>
void pair<_t>::operator++()
{
   first++;
   second++;
}

template <typename _t>
void pair<_t>::operator++(int)
{
   first++;
   second++;
}

Author:  JessT0 [ Thu Mar 18, 2004 11:48 am ]
Post subject: 
thank to Wtd alot. i got what you talking about.One more question:For the print and increment, I believe my instructor wants you to use operator overloading instead of creating a normal function. Do you have any idea for that?i'm really appreceate.
Author:  wtd [ Thu Mar 18, 2004 3:19 pm ]
Post subject: 
JessT0 wrote:
thank to Wtd alot. i got what you talking about.One more question:For the print and increment, I believe my instructor wants you to use operator overloading instead of creating a normal function. Do you have any idea for that?i'm really appreceate.


That's what the following functions are doing:

code:
template <typename _t>
std::ostream& operator<<(std::ostream& out, const pair<_t>& p)
{
   return out << p.first << "\t" << p.second;
}

// Prefix ++ operator:
// ++p;
template <typename _t>
void pair<_t>::operator++()
{
   first++;
   second++;
}

// Postfix ++ operator:
// p++;
template <typename _t>
void pair<_t>::operator++(int)
{
   first++;
   second++;
}
Author:  JessT0 [ Sat Mar 20, 2004 9:23 am ]
Post subject: 
One last question.Can we use print(),increment() functions which already have in there instead of using operator++(),operator++(int) and "cout" ?. Last time i just wanna say thank you very much for your help,this really helpfull.Have a good weekend
Author:  wtd [ Sat Mar 20, 2004 3:28 pm ]
Post subject: 
You can use them, but with the overloaded operators, you don't really have any reason to.

Which would you rather see?

code:
pair<int> p(3, 4);
p.increment();
p.print();


Or:

code:
pair<int> p(3, 4);
p++;
std::cout << p << std::endl;
Author:  JessT0 [ Sun Mar 21, 2004 11:46 pm ]
Post subject: 
thanks ,i get it now Smile

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