C++ Templates

Templates in C++, are basically the foundation of the generic programming, that involves, writing the code, that is independent of any specific type.

C++ Template Example

Here is an example program illustrating templates in C++:

/* C++ Templates - Example Program */

#include<iostream.h>
#include<string.h>
#include<conio.h>
template <typename T>
inline T const& Max(T const& num1, T const& num2)
{
   return num1<num2?num2:num1;
}
void main()
{
   clrscr();
   int a, b;
   cout<<"Enter any two number: ";
   cin>>a>>b;
   cout<<"Max("<<a<<", "<<b<<"): "<<Max(a, b)<<"\n";
   getch();
}

Here is the sample run of the above C++ program:

Enter any two number: 20
10
Max(20, 10): 20

Here is another example program, also demonstrating the template in C++

/* C++ Templates - Example Program */
      
#include<iostream.h>
#include<vector.h>
#include<conio.h>
#include<cstdlib.h>
#include<stdexcept.h>
#include<string.h>
using namespace std;
template <class T>
class STACK
{
   private:
      vector<T> elem;
   public:
      void push(T const&);
      void pop();
      T top() const;
      bool empty() const
      {
         return elem.empty();
      }
};
template <class T>
void STACK<T>::push(T const& ele)
{
   elem.push_back(ele);
}
template <class T>
void STACK<T>::pop()
{
   if(elem.empty())
   {
      throw out_of_range("STACK<>::pop():empty stack");
   }
   elem.pop_back();
}
template <class T>
T STACK<T>::top() const
{
   if(elem.empty())
   {
      throw out_of_range("STACK<>::top():empty stack");
   }
   return elem.back();
}
void main()
{
   clrscr();
   try
   {
      STACK<int> intstack;
      STACK<string> stringstack
      intstack.push(9);
      cout<<instack.top()<<"\n";
      stringstack.push("Hello");
      cout<<stringstack.top()<<std::endl;
      stringstack.pop();
      stringstack.pop();
   }
   catch(exception const& e)
   {
      cerr<<"Exception: "<<e.what()<<"\n";
      getch();
      exit(1);
   }
   getch();
}

Below is the sample run of the above C++ program:

9
Hello
Exception: STACK<>::pop():empty stack