Question

Linux and C

Write a program that will calculate the nthelement of such an extended Fibonacci sequence. For example, assuming that your executable program was called efib and that the shell prompt is "bash-4.4$ ", interaction with your program might be as follows: bash-4.4$./efib Enter a number: 0 F(0) is 0 bash-4.4$ /efib Enter a number: 1 F (1) is 1 bash-4.4$./efib Enter a number:1 P (-1) is 1 bash-4.4$ /efib Enter a number: 6 F(6) is 8 bash-4.4$/efib Enter a number-9 F(-9) is 34 bash-4.4$ ./efib Enter a number:10 F(-10) is -55 bash-4.4$

Answer 1

/* C program to calculate nth Fibonacci number */

#include<stdio.h>
#include<math.h>
int fib(int);       /* function prototype */
void main()
{
int n,t;
printf("enter a number: ");
scanf("%d",&n);
t=abs(n);   /* predefined function to change negative number to postive number*/
printf("F(%d) is %d\n",n,fib(t));   /* function call in printf statement */
}
int fib(int m) /* function definition */
{
   if(m==0)
   return 0;
   else if(m==1)
   return 1;
   else
   return fib(m-1)+fib(m-2); /* recursive call to fib funcion */
}

Output:

netsem2014@netsem2014-VirtualBox: netsen2014@netsem2014-VirtualBox vi fibonacci.c netsen2014@netsen2014-VirtualBox- gcc fibonacci.c o efib netsen2014@netsen2014-VirtualBox $/efib enter a number: 0 F(0) is 0 netsem2014@netsem2014-VirtualBox:-/efib enter a number: 1 F(1) is 1 netsen2014@netsem2014-VirtualBox:-$ ./efib enter a number: -1 F(-1) is 1 netsem2014@netsem2014-VirtualBox:-./efib enter a number: 6 F(6) is 8 netsen2014@netsen2014-VirtualBox: $/efib enter a number: 9 F(-9) is 34 netsem2014@netsem2014-VirtualBox: ./efib enter a number: 10 F(-10) is 55