Program to find first 20 Fabonacci series

#include<stdio.h>
void main()
{
    int k,r=20;
    long int i=0l,j=1,f;
    clrscr();
    //Taking maximum numbers form user

    printf("FIBONACCI SERIES:\n ");
    printf("%ld %ld",i,j); //printing firts two values.

    for(k=2;k<r;k++){
f=i+j;
i=j;
j=f;
printf(" %ld",j);
    }