Recursion in C

Recursion in C

When function is called within the same function, it is known as recursion in C. The function which calls the same function, is known as recursive function.

A function that calls itself, and doesn't perform any task after function call, is know as tail recursion. In tail recursion, we generally call the same function with return statement. An example of tail recursion is given below.

Let's see a simple example of recursion.

1. recursionfunction(){  
2.   
3. recursionfunction();//calling self function  
4.   
5. }  

Example of tail recursion in C

Let's see an example to print factorial number using tail recursion in C language.

1. #include<stdio.h>  
2. #include<conio.h>  
3. int factorial (int n)  
4. {  
5.     if ( n < 0)  
6.         return -1; /*Wrong value*/  
7.     if (n == 0)  
8.         return 1; /*Terminating condition*/  
9.     return (n * factorial (n -1));  
10. }  
11.   
12. void main(){  
13. int fact=0;  
14. clrscr();  
15. fact=factorial(5);  
16. printf("\n factorial of 5 is %d",fact);  
17.   
18. getch();  
19. }  

Output

factorial of 5 is 120

We can understand the above program of recursive method call by the figure given below: