When a function calls itself, and this process is known as recursion. The function that calls itself is known as a recursive function.
Recursive function comes in two phases :
* Winding phase
* Unwinding phase
Winding phase : When the recursive function calls itself, and this phase ends when the condition is reached.
Unwinding phase : Unwinding phase starts when the condition is reached, and the control returns to the original call.
Example of recursion :
#include <stdio.h>
int calculate_fact(int);
int main()
{
int n=5,f;
f=calculate_fact(n); // calling a function
printf("factorial of a number is %d",f);
return 0;
}
int calculate_fact(int a)
{
if(a==1)
{
return 1;
}
else
return a*calculate_fact(a-1); //calling a function recursively.
}
Output :
factorial of a number is 120
