Recursive function

//Program to write recursive function for
//a)Tower of hanoi
//b)power of x to n
//c)Fibonacci series

#include <stdio.h>

void TOH(int n, char A, char B , char C)
  {
     if(n>0)
{
TOH(n-1,A,C,B);
printf("\n%c->%c",A,B);
TOH(n-1,C,B,A);
}
  }
int fib(int n)
  {
     if(n==0)
return(0);
     if(n==1)
return(1);
     return(fib(n-1)+fib(n-2));
  }
int power(int x , int n)
  {
      if(n==0)
return(1);
      return(x*power(x,n-1));
  }
int main()
  {
     int n,x,op,i;
     do
{
printf("\n1)Tower of Hanoi\n2)Power of x to the n");
printf("\n3)Fibonacci series\n4)Quit");
printf("\nEnter Your choice : ");
scanf("%d",&op);
switch(op)
  {
case 1: printf("\nEnter No. of plates : ");
scanf("%d",&n);
TOH(n,'A','B','C');
break;
case 2: printf("\nEnter x and n : ");
scanf("%d%d",&x,&n);
printf("%d",power(x,n));
break;
case 3: printf("\nEnter No. of Terms: ");
scanf("%d",&n);
for(i=0;i<n;i++)
  printf("%d  ",fib(i));
break;

 }
  }while(op!=4);
  }