Program for Fibonacci numbers in C

CServer Side ProgrammingProgramming

Given with ‘n’ numbers the task is to generate the fibonacci series till starting from 0 to n where fibonacci series of integer is in the form

0, 1, 1, 2, 3, 5, 8, 13, 21, 34

Where, integer 0 and 1 will have fixed space, after that two digits are added for example,

0+1=1(3rd place)
1+1=2(4th place)
2+1=3(5th place) and So on

Sequence F(n) of fibonacci series will have recurrence relation defined as −

Fn = Fn-1 + Fn-2
Where, F(0)=0 and F(1)=1 are always fixed

There can be multiple approaches that can be used to generate the fiboacce series −

Recursive approach − in this, approach function will make a call to itself after every integer value. It is simple and easy to implement but it will lead to exponential time complexity which makes this approach ineffective.

Using For Loop − By using For loop in generating Fibonacci series time complexity can be reduced to O(n) which makes this approach effective.


Input-: n=10
Output-: 0 1 1 2 3 5 8 13 21 34


Step 1 -> Declare function for Fibonacci series
   Void Fibonacci(int n)
      Declare variables as int a=0,b=1,c,i
      Print a and b
      Loop For i=2 and i<n and ++i
         Set c=a+b
         Print c
         Set a=b
         Set b=c
Step 2 -> In main()
   Declare int as 10
   Call Fibonacci(n)


void fibonacci(int n){
   int a=0,b=1,c,i;
   printf("fibonacci series till %d is ",n);
   printf("\n%d %d",a,b);//it will print 0 and 1
   for(i=2;i<n;++i) //loop starts from 2 because 0 and 1 are the fixed values that series will take{
      printf(" %d",c);
int main(){
   int n=10;
   return 0;


fibonacci series till 10 is
0 1 1 2 3 5 8 13 21 34
Published on 20-Sep-2019 18:03:46