# C program to find Fibonacci series

### Definition

We assume first two Fibonacci are 0 and 1

A series of numbers in which each sequent number is sum of its two previous numbers is known as Fibonacci series and each numbers are called Fibonacci numbers. So Fibonacci numbers is

Fn = Fn-2 + Fn-1

### Example of Fibonacci series:

0 , 1 ,1 , 2 , 3 , 5 , 8 , 13 , 21 , 34 , 55 ...

5 is Fibonacci number since sum of its two previous number i.e. 2 and 3 is 5

8 is Fibonacci number since sum of its two previous number i.e. 3 and 5 is 8 and so on.

#include
int main(){
int k,r;
long int i=0l,j=1,f;
//Taking maximum numbers form user
printf("Enter the number range:");
scanf("%d",&r);
printf("FIBONACCI SERIES: ");
printf("%ld %ld",i,j); //printing firts two values.
for(k=2;k f=i+j;
i=j;
j=f;
printf(" %ld",j);
}
return 0;
}

## C program for Fibonacci series using array

#include
int main(){
int i,range;
long int arr;
printf("Enter the number range: ");
scanf("%d",&range);
arr=0;
arr=1;
for(i=2;i arr[i] = arr[i-1] + arr[i-2];
}
printf("Fibonacci series is: ");
for(i=0;i printf("%ld ",arr[i]);
return 0;
}

## C program to calculate Fibonacci series using while loop

#include
int main(){
int k=2,r;
long int i=0l,j=1,f;
printf("Enter the number range:");
scanf("%d",&r);
printf("Fibonacci series is: %ld %ld",i,j);
while(k f=i+j;
i=j;
j=f;
printf(" %ld",j);
k++;
}
return 0;
}

## C Program for Sum of Fibonacci series

#include
int main(){
int k,r;
long int i=0,j=1,f;
long int sum = 1;
printf("Enter the number range: ");
scanf("%d",&r);
for(k=2;k f=i+j;
i=j;
j=f;
sum = sum + j;
}
printf("Sum of Fibonacci series is: %ld",sum);
return 0;
}