How to check fibonacci number c program code example

Example: c how to fibonacci

#include <stdio.h>
#include <stdlib.h>

int main() {
	long int a = 1,b = 2, c, d, cont = 0;
	double e, f;
	
	printf("Fibonacci fino a: ");
	scanf("%ld", &c);
	
	while(b < c)
	{
		cont ++;
		printf("\n%ld", b);
		d = a;
		a = b;
		b = b + d;
	}
	
	f = (double)b / (double)a;
	
	e = (double)cont / (double)c * (double)100;
	
	printf("\n\nOttenuto: %lf\nPercentuale: %lf\n\n\n", f, e);
	
	system("pause");
}