Recursion in c

When function is called within the same function, it is known as recursion in C.
In programming, there might be a situation where a function needs to invoke itself.
The C language supports recursive feature, i.e. a function is called repetitively by itself. The recursion can be used directly or indirectly.
The direct recursion function calls to itself till the condition is true. In indirect recursion, a function calls another function, then the called function calls the calling function.

Types of Recursion

There are two types of Recursion

Direct recursion
Indirect recursion

Example:

#include <stdio.h>
int x,s;
void main(int);

void main(x)

{
      s=s+x;
      printf("\n x = %d s = %d",x,s);
      if(x==5)
      exit(0);
      main(++x);
}

Output:

x = 1 s = 1

x = 2 s = 3

x = 3 s = 6

x = 4 s= 10

x = 5 s= 15

Disadvantages of Recursion

It consumes more storage space the recursive calls along with automatic variables are stored on the stack.
The computer may run out of memory if the recursive calls are not checked.
It is not more efficient in terms of speed and execution time.
According to some computer professionals, recursion does not offer any concrete advantage over non-recursive procedures/functions.
Recursive solution is always logical and it is very difficult to trace.(debug and understand).
In recursive we must have an if statement somewhere to force the function to return without the recursive call being executed, otherwise the function will never return.
Recursion takes a lot of stack space, usually not considerable when the program is small and running on a PC.
Recursion uses more processor time.
Recursion is not advocated when the problem can be through iteration.
Recursion may be treated as a software tool to be applied carefully and selectively.