用for循环求斐波拉契数列

#include <stdlib.h>
#include <stdio.h>
int fib(int n)
{
	int first = 1;
	int second = 1;
	int ret;
	int i;
	for (i=3;i <=n; i++)
	{
		ret = first + second;
		first = second;
		second = ret;
	}
	return ret;
}
int main()
{

		int n;
		scanf("%d", &n);
		printf("%d\n", fib(n));
	    system("pause");
	    return 0;
}