1 семестр / sr5

#include <stdio.h>
#include <math.h>
int main(void)
{
    int k=-2;
    long double n=0.0;
    double sum=0.0;
    double ansum=(M_PI)/4.0;
    while (fabs(sum-ansum)>(long double)0.00000001){
        ++k;
        ++n;
        if (k%2==0)
            sum-=(long double)1/(2*n-1);
        else
            sum+=(long double)1/(2*n-1);
    }
    printf("%.8f\n", ansum);
    printf("%.8f\n", sum);
    printf("%.8f\n", fabs(sum-ansum));
    printf("%d\n", k);
}