C programs to practice -Find the factorial of given number by recursion

     Factorial is the continuous multiplication of the number from 1,2,…upto the number. Using recursion concept, this can be achieved easily.

Program :”factrec.c”

#include<stdio.h>

#include<conio.h>

int factorial(int n)

{

if (n<=1)

 return(1);

else

 return(n*factorial(n-1));

}

void main()

{

 int  n,fact=0;

printf(“ Enter the number”);

scanf(“%d”,&n);

fact= factorial(n);

printf(“The factorial of %d is : %d”,n,fact);

getch();

}

 

Output:

Enter the number 5

The factorial of 5 is 120

 

Now,let us try some interesting number series called Fibonacci series….

First,get the number of elements for the series as ‘n’. 

Using a loop, repeat the process until the number reaches to n.

Add the last two number and print the number.

Once the loop is finished, close the program.

Now, the program begins….

“Fibonacci.c”

#include <stdio.h>

int fibonacci(int x)

{

  if (x==0) { return(0); }

  else if(x==1) { return( 1);}

 return fibonacci(x-1)+fibonacci(x-2);

}

void main()

{

  int n,x;

  printf("Enter the number of elements");

  scanf("%d",&n);

  for(x=0;x<n;x++)

  {

   printf("%d \t \n" ,fibonacci(x);

  }

  getch();

}

the output is given below....

Enter the number of elements  7

0

1

1

2

3

5

8