What are recursive functions used for?

[ineedhelpnow]

Hi

Recursion. Recursive functions. What are they used for and how they helpful?

 

[kaliprasad]

Technically, a recursive function is a function that makes a call to itself. To prevent infinite recursion, you need an if-else statement (of some sort) where one branch makes a recursive call, and the other branch does not. This branch that does not make a recursive call becomes the terminating condition. Mathematically it should have a recursive definition.

for an example we know

factorial (1) =1

factorial ( n) = factorial (n-1) * n for n > 1

this can be coded as

#include <stdio.h>

int factorial(unsigned int i)
{
if(i <= 1)
{
return 1;
}
return i * factorial(i - 1);
}

this can be converted to

int factorial(unsigned int i)
{
int product = 1;
while (i) {
product = product * i;
i--;
}
return product;
}SOme times it may not be easy to convert particlularly for mutually recursive function say parsing of expression and so on and it is best to leave it as it is.