Program 1: print Fibonacci series in c

#include<stdio.h>
int main(){

    int i,range;
    long int arr[40];

    printf("Enter the number range: ");
    scanf("%d",&range);

    arr[0]=0;
    arr[1]=1;

    for(i=2;i<range;i++){
         arr[i] = arr[i-1] + arr[i-2];
    }

    printf("Fibonacci series is: ");
    for(i=0;i<range;i++)
         printf("%ld ",arr[i]);
  
    return 0;
}

Result

Enter the number range: 20
Fibonacci series is: 0 1 1 2 3 5 8 13 21 34 55 89 144 233 377 610 987 1597 2584 4181

Program 2: Fibonacci series in c using while loop

#include<stdio.h>
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<r){
         f=i+j;
         i=j;
         j=f;
         printf(" %ld",j);
          k++;
    }
  
    return 0;
}

Result

Enter the number range: 10
Fibonacci series is: 0 1 1 2 3 5 8 13 21 34

Program 3: Sum of Fibonacci series in c

#include<stdio.h>
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<r;k++){
         f=i+j;
         i=j;
         j=f;
         sum = sum + j;
    }

    printf("Sum of Fibonacci series is: %ld",sum);
  
    return 0;
}

Result

Enter the number range: 4
Sum of Fibonacci series is: 4

Program 4: To print the fibonacci series using recursion

#include <stdio.h>
#include <conio.h>
unsigned long fib(int);
void main()
{
	int n,i;
	unsigned long f;
	clrscr();
	printf("\nENTER A NUMBER: ");
	scanf("%d",&n);
	printf("\nTHE FIBONNACI SERIES UPTO %d NUMBERS IS:\n",n);
	for(i=0;i<n;i++)
	{
		f=fib(i);
		printf("%lu ",f);
	}
	getch();
}
unsigned long fib(int x)
{
	unsigned long res;
	if(x==0)
		return(0);
	else
		if(x==1)
			return(1);
		else
		{
			res=fib(x-1)+fib(x-2);
			return(res);
		}
}

Result

ENTER A NUMBER: 10
THE FIBONNACI SERIES UPTO 10 NUMBERS IS
0 1 1 2 3 5 8 13 21 34