Templates are a feature of the C++ programming language that allow functions and classes to operate with generic types. This allows a function or class to work on many different data types without being rewritten for each one.
 
Templates are of great utility to programmers in C++, especially when combined with multiple inheritance and operator overloading. The C++ Standard Library provides many useful functions within a framework of connected templates.
 
Templates are of two types :
1. Function templates
2. Class templates

1.Function templates

A function template behaves like a function except that the template can have arguments of many different types. See the following example for adding two generic numbers with the help of function templates :

#include <iostream>
using namespace std;

template<typename Type> // template declaration
Type gettingSum(Type a, Type b)
{
	return a + b; // will return sum
}

int main()
{
	cout << "for integers sum is  : " << gettingSum(2, 3) << endl;
	cout << "for floats sum is : " << gettingSum(2.3, 3.6);
	return 0;
}

Output of the above program is :

for integers sum is  : 5
for floats sum is : 5.9

regardless of any typecasting, redefining variables etc. This is how templates are very useful