Templates in C++ allow you to construct generic code that can deal with multiple data types without having to replicate the code for each one. In C++, templates are fundamental for constructing flexible and reusable classes and functions. In C++, there are two types of templates: function templates and class templates.

1. Function Templates:

Function templates allow you to create generic functions that can operate on different data types. You define a function template by specifying a placeholder for the data type. Here's a basic example of a function template that swaps two values of any data type:

#include<iostream.h>

#include<conio.h>

template<class T>

void display(T x,T y)

{

T result;

result=x+y;

cout<<"Addition is\n"<<result<<endl;

}

void main()

{

clrscr();

display(4,5);

display(5.7,6.7);

getch();

}

2. Class Templates:

Class templates allow you to define generic classes. You can create a class template with one or more template parameters. Here's a simple example of a class template for a stack data structure:

#include<iostream.h>

#include<conio.h>

template<class T>

class A

{

T a;T b;

public:

void display();

void print();

};

template<class T>

void A<T>::display()

{

cout<<"enter the value of a\n";

cin>>a;

cout<<"Enter the value of b\n";

cin>>b;

}

template<class T>

void A<T>::print()

{

cout<<a<<endl<<b;

}

void main()

{

clrscr();

A<int> a1;

a1.display();

a1.print();

getch();

}