Fibonacci numbers

fibonacci.c

#include <stdio.h>
#include <stdarg.h>
#include <conio.h>
#include <math.h>
#include <stdlib.h>

int main(int argc, char const *argv[])
{
	printf("Fibonacci numbers\n");
	int f, i, prev, beforePrev;

	for (i = 1; i <= 20; i++) {
		if (i <= 2) {
			f = 1;
		} else {
			f = beforePrev + prev;
		}
		
		printf("%d\n", f);

		beforePrev = prev;
		prev = f;
	}
	
	return 0;
}