double epsilon = 1e-18D;

void setup() {
  testIsClose(100000000000000.01D, 100000000000000.011D, epsilon);
  testIsClose(100.01D, 100.011D, epsilon);
  testIsClose(10000000000000.001D / 10000.0D, 1000000000.0000001000D, epsilon);
  testIsClose(0.001D, 0.0010000001D, epsilon);
  testIsClose(0.000000000000000000000101D, 0.0D, epsilon);
  testIsClose(Math.sqrt(2) * Math.sqrt(2), 2.0D, epsilon);
  testIsClose(-Math.sqrt(2) * Math.sqrt(2), -2.0D, epsilon);
  testIsClose(3.14159265358979323846D, 3.14159265358979324D, epsilon);
  exit();  // all done
}


boolean isClose(double num1, double num2, double epsilon) {
  return Math.abs(num2 - num1) <= epsilon;
}


void testIsClose(double num1, double num2, double epsilon) {
  boolean result = isClose(num1, num2, epsilon);
  if (result) {
    println("True. ", num1, "is close to", num2);
  } else {
    println("False. ", num1, "is not close to", num2);
  }
}