Learning to Program

Write a program to calculate the factorial of a number. Use the concept of recursion instead of using loops. #include <stdio.h> main ( ) { int a , fact ; printf ( " \n Enter any number: " ) ; scanf ( "%d" , & a ) ; fact = rec ( a ) ; printf ( " \n Factorial Value = %d" , fact ) ; } rec ( int x ) { int f ; if ( x = = 1 ) return ( 1 ) ; else f = x * rec ( x - 1 ) ; return ( f ) ; }

Write a recursive function to obtain the first 25 numbers of a Fibonacci sequence. In a Fibonacci sequence the sum of two successive terms gives the third term. Following are the first few terms of the Fibonacci sequence: 1 1 2 3 5 8 13 21 34 55 89 ... #include <stdio.h> main ( ) { static int prev_number = 0 , number = 1 ; // static : so value is not lost int fibonacci ( int prev_number , int number ) ; printf ( "Following are the first 25 Numbers of the Fibonacci Series: \n " ) ; printf ( "1 " ) ; // to avoid complexity fibonacci ( prev_number , number ) ; } fibonacci ( int prev_number , int number ) { static int i = 1 ; // i is not 0 , cuz 1 is already counted in main . int fibo ; if ( i = = 25 ) { printf ( " \n done" ) ; // stop after 25 numbers } else { fibo = prev_number + number ; prev_number = number ; // important steps number = fibo ; printf ( " \n %d" , fibo ) ; i + + ; // increment