Fibonacci Series in C language with Example

Fibonacci Series in C

Fibonacci Series: Fibonacci sequence or Fibonacci Series is a series where the next number is the sum of pervious two numbers. The first two terms of the Fibonacci sequence is 0 followed by 1. 

For Example

The Fibonacci sequence or Fibonacci Series: 0, 1, 1, 2, 3, 5, 8, 13, 21 etc. The first two numbers of fibonacci series are 0 and 1.

Lets understan using This Image:


There are two ways to write the fibonacci series program:
  • Fibonacci Series without recursion
  • Fibonacci Series using recursion

Fibonacci Series in C without recursion

Let's see the fibonacci series program in c without recursion.
  1. #include<stdio.h>  
  2. #include<conio.h>  
  3. void main()  
  4. {  
  5.  int n1=0,n2=1,n3,i,number;  
  6.  clrscr();  
  7.  printf("Enter the number of elements:");  
  8.  scanf("%d",&number);  
  9.  printf("\n%d %d",n1,n2);//printing 0 and 1  
  10.   
  11.  for(i=2;i<number;++i)//loop starts from 2 because 0 and 1 are already printed  
  12.  {  
  13.   n3=n1+n2;  
  14.   printf(" %d",n3);  
  15.   n1=n2;  
  16.   n2=n3;  
  17.  }  
  18. getch();  
  19. }  
Output:
Enter the number of elements:15
0 1 1 2 3 5 8 13 21 34 55 89 144 233 377 

Fibonacci Series using recursion in C

Let's see the fibonacci series program in c using recursion.
  1. #include<stdio.h>  
  2. #include<conio.h>  
  3. void printFibonacci(int n){  
  4.     static int n1=0,n2=1,n3;  
  5.     if(n>0){  
  6.          n3 = n1 + n2;  
  7.          n1 = n2;  
  8.          n2 = n3;  
  9.          printf("%d ",n3);  
  10.          printFibonacci(n-1);  
  11.     }  
  12. }  
  13. void main(){  
  14.     int n;  
  15.     clrscr();  
  16.     printf("Enter the number of elements: ");  
  17.     scanf("%d",&n);  
  18.   
  19.     printf("Fibonacci Series: ");  
  20.     printf("%d %d ",0,1);  
  21.     printFibonacci(n-2);//n-2 because 2 numbers are already printed  
  22.   
  23.     getch();  
  24. }  
Output:
Enter the number of elements:15
0 1 1 2 3 5 8 13 21 34 55 89 144 233 377 


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