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