【C语言】有一分数序列：2/1，3/2，5/3，8/5，13/8，21/13... 求出这个数列的前20项之和

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

int main()
{
	float numerator = 2.0;    //分子
	float denominator = 1.0;  //分母
	float sum = 0;
	float tmp;
	for (int i = 0; i < 20; i++)
	{
		sum += numerator / denominator;
		tmp = numerator;
		numerator = numerator + denominator;
		denominator = tmp;
	}
	printf("%f\n", sum);
	system("pause");
	return 0;
}