Recursion

When a function calls itself, new local variables and parameters are allocated storage (usually on the system stack), and the function code is executed with these new variables from the start.
The existence of functions makes possible a programming technique called recursion.
Recursion involves a function calling itself.

Example

#include <iostream>
using namespace std;

unsigned long factfunc(unsigned long); //declaration

   int main()
    {
     int n; //number entered by user 
     unsigned long fact; //factorial

     cout > n;
     fact = factfunc(n);
     cout << “Factorial of “ << n << “ is “ << fact << endl;
     return 0;
    } 
// factfunc() 
// calls itself to calculate factorials 
unsigned long factfunc(unsigned long n)
 { 
  if(n > 1)
    return n * factfunc(n-1); //self call 
  else
    return 1;
 }

Output

Enter a number: 10 
Factorial is 3628800

Function Overloading

In this section, you will learn about one of C++’s most exciting features: function overloading. In C++, two or more functions can share the same name as long as their parameter declarations are different.
In this situation, the functions that share the same name are said to be overloaded, and the process is referred to as function overloading.
Function overloading is one way that C++ achieves polymorphism.

Example

#include <iostream>
using namespace std;

void f(int i);

int main()
 {
   f(10);
   return 0;
 }
void f(int i)
{
  cout << " In f(int), i is " << i << '
';
}

Output

 In f(int), i is 10