Recursion is a common method of simplifying a problem into subproblems of same type. This is called divide and conquer technique. A basic example of recursion is factorial function.

Example:

int factorial(int n){

if(n==0) return 1;

else return (n* factorial(n-1));

}

In above factorial example : factorial function calles itself by multiplying n with factorial of n-1 and stops when it reaches to the bas condition at fact 0  by returning 1.

So function calling done in the following way.

fact(5).

5*fact(4) //calls fact(4)

5*4*fact(3)

5*4*3*fact(2)

5*4*3*2*fact(1)

5*4*3*2*1*fact(0)

5*4*3*2*1*1 // stops here