Program : 14

PROGRAM - 14

a) Write a program to perform the following using recursion

i)      To find the factorial of a given integer.

ii) To find the GCD(Greatest Common Divisor) of two given  integers.

iii)  To solve the towers of Hanoi Problem.

Program to find the factorial of a given integer:

#include<stdio.h>

#include<conio.h>

main()

{

     int n, res;

     int fact(int);

     clrscr();

     printf("enter a number:");

     scanf("%d",&n);

     res=fact(n);

     printf("the factorial of %d is %d",n,res);

     getch();

}

    int fact(int n)

    {

     int res;

     if(n==1)

     return 1;

     else

     {

        res=n*fact(n-1);

        return res;

     }

}

/*

INPUT: enter a number:7

OUTPUT: the factorial of 7 is 5040

*/

Program to find the gcd of two given integers:

#include<stdio.h>

#include<conio.h>

main()

{

     int m,n;

     void gcd(int,int);

     clrscr();

     printf("enter the values for m and n");

     scanf("%d %d",&m,&n);

     gcd(m,n);

     getch();

}

void gcd(int m,int n)

{

     int a,b,r;

     a=m;

     b=n;

     r=m%n;

     while(r!=0)

     {

          m=n;

          n=r;

          r=m%n;

     }

     printf("gcd(%d,%d)=%d",a,b,n);

     getch();

}

/*

INPUT: enter the values for m and n 23 41

OUTPUT: gcd(23,41)=1                       */

Program to solve the towers of hanoi problem:

#include<stdio.h>

#include<conio.h>

main()

{

     int nvalue;

     char snvalue='L',invalue='C',dnvalue='R';

     void hanoi(int,char,char,char);

     clrscr();

     printf("enter number of disks:");

     scanf("%d",&nvalue);

     printf("\ntowers of hanoi problem with %d disks"

                                             ,nvalue);

     hanoi(nvalue,snvalue,invalue,dnvalue);

     getch();

}

void hanoi(int n,char snd,char ind,char dnd)

{

  if(n!=0)

  {

    hanoi(n-1,snd,dnd,ind);

    printf("\nmove disk %d from %c to %c \n"

                                      ,n,snd,dnd);

    hanoi(n-1,ind,snd,dnd);

  }

}

/*

INPUT:enter number of disks:3

OUTPUT:

towers of hanoi problem with 3 disks

move disk 1 from L to R

move disk 2 from L to C

move disk 1 from R to C

move disk 3 from L to R

move disk 1 from C to L

move disk 2 from C to R

move disk 1 from L to R

*/