RosettaCodeData/Task/Eulers-constant-0.5772.../Java/eulers-constant-0.5772....java

/**
 * Using a simple formula derived from Hurwitz zeta function,
 * as described on https://en.wikipedia.org/wiki/Euler%27s_constant,
 * gives a result accurate to 12 decimal places.
 */
public class EulerConstant {

    public static void main(String[] args) {
        System.out.println(gamma(1_000_000));
    }

    private static double gamma(int N) {
        double gamma = 0.0;

        for ( int n = 1; n <= N; n++ ) {
            gamma += 1.0 / n;
        }

        gamma -= Math.log(N) + 1.0 / ( 2 * N );

        return gamma;
    }

}