One C language programming every day (seeking PI)

topic description

Use the pi/4=1-1/3+1/5-1/7... formula to find the approximate value of pi, when the absolute value of a certain item is less than 10^-6

output format

 Approximate values ​​of PI are rounded to six decimal places

 problem solving ideas

The code here is easy to understand, just pay attention to i, sum must be defined as a floating point number

This condition is always true if i is of type int, since 1/ithe result of will be truncated to an integer

#include <stdio.h>

int main()
{
    double sum=0,i = 1, k = 1;
    double pi;
    while (1.0 / i >= 1E-6)
    {
        sum += k / i;
        k = k * (-1);//k取反
        i += 2;//等差数列
    }
    pi = sum * 4;
    printf("%.6lf", pi);
    return 0;
}