计算1-1/3+1/5-1/7+……

Question

读入一个正实数eps, 计算并输出1-1/3+1/5-1/7+……，直到最后一项的绝对值小于eps。
例:
输入:1E-4
输出:0.785348
输入:0.1
输出:0.834921

Answer 1

#include <stdio>
#include <math>

int main()
{
    double eps;
    scanf("%lf", &eps);
    double f = 1.0;
    double sum = f;
    int count = 0;
    while(abs(f) >= eps)
    {
        count++;
        f = (count%2==0?1.0:-1.0)/(2.0*count+1);
        sum += f;
    }
    printf("%lf", sum);
    return 0;
}