神马品牌网中国关税税率表2017:有一分数数列:2/1, 3/2, 5/3, 8/5, 13/8, 21/13, ...求这数列前20项之和?
来源：百度文库 编辑：神马品牌网 时间：2024/05/02 04:19:51
int main()
{
double sum = 0;
int i, a = 1, b = 1, c;
for(i = 1; i <= 20; i++)
{
c = a;
a = a + b;
b = c;
sum = sum + a / b;
//printf("%d/%d ", a, b); //这是用于检验的一段代码
}
printf("%f", sum);
getchar();
}
或者：
int main()
{
double sum = 0;
int a[21] = {1,2,3,5,8,13,21,34,55,89,144,233,377,610,987,1597,2584,4181,6765,10946,17711};
int i;
for(i = 0; i != 20; i++)
{
sum = sum + a[i+1] / a[i];
}
printf("%f", sum);
getchar();
}
VB编的，结果是32.66
Dim A(1 To 20) As Long, B(1 To 20) As Long
Dim U As Double, I As Long
U = 0: A(1) = 2: B(1) = 1: A(2) = 3: B(2) = 2
U = 2 / 1 + 3 / 2
For I = 3 To 20
A(I) = A(I - 1) + A(I - 2)
B(I) = B(I - 1) + B(I - 2)
U = U + A(I) / B(I)
Next
MsgBox U