SOME SIMPLE PROGRAMS USING RECURSION

Develop recursive programs for the following questions:

Question # 1

Display the following series using recursion:

1, 2, 3, 4, 5, 6, 7, 8……20

/***********************************************************************************/

#include<stdio.h>

#include<conio.h>

void print(int);

int main()

{

                print(20);

                getch();

                return 0;

}

void print(int n)

{

                if(n==0)

                                return;

                print(n-1);

                printf("%d\t",n);

}

/***********************************************************************************/

Question # 2

Display the following series using recursion:

20 , 19 , 18 , 17 , 16 …. 2 , 1

/***********************************************************************************/

#include<stdio.h>

#include<conio.h>

void print(int);

int main()

{

                print(20);

                getch();

                return 0;

}

void print(int n)

{

                if(n==0)

                                return;

                printf("%d\t",n);

                print(n-1);

}

/***********************************************************************************/

Question # 3

Calculate the factorial of a given number using recursion.

/***********************************************************************************/

#include<stdio.h>

#include<conio.h>

long factorial(int);

int main()

{

                int num;

                clrscr();

                printf("Enter the number : ");

                scanf("%d",&num);

                printf("%ld",factorial(num));

                getch();

                return 0;

}

long factorial(int n)

{

                long fact;

                if(n==0)

                                return 1;

                fact=factorial(n-1)*n;

                return fact;

}

/***********************************************************************************/