Write a C program to print the Fibonacci series using recursion and without using recursion.

Sure, here are the C programs to print the Fibonacci series using recursion and without using recursion.

1. Fibonacci series using recursion:

#include<stdio.h>

void printFibonacci(int n){
    static int n1=0,n2=1,n3;
    if(n>0){
        n3 = n1 + n2;
        n1 = n2;
        n2 = n3;
        printf("%d ",n3);
        printFibonacci(n-1);
    }
}

int main(){
    int n;
    printf("Enter the number of elements: ");
    scanf("%d",&n);
    printf("Fibonacci Series: ");
    printf("%d %d ",0,1);
    printFibonacci(n-2);  //n-2 because 2 numbers are already printed
    return 0;
}

2. Fibonacci series without using recursion:

#include<stdio.h>

int main(){
    int n, n1 = 0, n2 = 1, n3, i;
    printf("Enter the number of elements: ");
    scanf("%d",&n);
    printf("Fibonacci Series: ");
    printf("%d %d ",n1,n2); //printing 0 and 1
    for(i=2;i<n;++i) //loop starts from 2 because 0 and 1 are already printed
    {
        n3 = n1 + n2;
        printf("%d ",n3);
        n1 = n2;
        n2 = n3;
    }
    return 0;
}

In both programs, the user is asked to enter the number of elements to be printed in the Fibonacci series. The first two numbers of the Fibonacci series are always 0 and 1. The next number is found by adding up the two numbers before it.