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n项之和的整数部分c语言代码

int n, i;
double numerator, denominator, temp = 0;
scanf("%d", &n);
numerator = 2.0;
denominator = 1.0;
for (i = 1; i <= n; i++) {
temp += numerator / denominator;
numerator += denominator;
denominator = numerator - denominator;
}
printf("%d\n", (int)temp);
return 0;