written 5.8 years ago by |
Recursion: It is a method of programming where a function calls itself directly or indirectly. Recursion is used as an alternative to iteration. Recursion is simply the use of a function which, as part of its own execution code, invokes itself.
Recursion will be useful when same kind of job has to be continued for a finite no input or time.
Eg: calculating series, finding factorial etc. It reduces unnecessary calling of function.
Example : Factorial of a number
// pseudo code for factorial
int factorial (n) { If (n==0)
Return 1;
else
{
return n* factorial(n-1)
}
}
Let us see how factorial () method is used recursively to compute factorial of 3:
Factorial (3) = 3 * factorial (2)
= 3 * (2* factorial (1))
= 3 * (2* (1*1))= 6
Hence by using recursion, the same function is reused multiple times.