import std.math;
import std.stdio;

auto approxEquals = (double a, double b, double epsilon) => abs(a - b) < epsilon;

void main() {
    void test(double a, double b) {
        double epsilon = 1e-18;
        writefln("%.18f, %.18f => %s", a, b, a.approxEquals(b, epsilon));
    }

    test(100000000000000.01, 100000000000000.011);
    test(100.01, 100.011);
    test(10000000000000.001 / 10000.0, 1000000000.0000001000);
    test(0.001, 0.0010000001);
    test(0.000000000000000000000101, 0.0);
    test(sqrt(2.0) * sqrt(2.0), 2.0);
    test(-sqrt(2.0) * sqrt(2.0), -2.0);
    test(3.14159265358979323846, 3.14159265358979324);
}