Question

Write a program to get an approximation of π with a precision of 10^(-5) using the following formula:
π=4.0×(1-1/3+1/5-1/7+⋯+〖(-1)〗^(n-1) 1/(2n-1))
hints:
initialize pi =0 and i=1
the absolute value of the adding item determines the precision you can get when putting more items to pi, thus
adding item: 〖(-1)〗^(i-1) 1/(2i-1), then
when abs(adding item) > precision,
update pi with pi += adding item

Answer 1

Собственно это вычисление числа Pi через ряд Лейбница:

#include <iostream>

using namespace std;

int main()

{

double pi = 0;

double sign = 1.;

const double eps = 1e-5;

int i = 0;

do

{

 pi += sign / (2. * i + 1.);

 sign = -sign;

 i++;

} while (1. / (2. * i + 1.) > eps);

pi *= 4;

printf("pi=%10.5lf", pi);

return 0;

}