public String calculateUnary(String operation, String value, boolean isDegree) try double num = Double.parseDouble(value); double result = 0; switch (operation) ": result = Math.abs(num); break; case "floor": result = Math.floor(num); break; case "ceil": result = Math.ceil(num); break; case "!": result = factorial((int) num); break; case "%": result = num / 100; break; case "π": result = Math.PI; break; case "e": result = Math.E; break; case "rand": result = Math.random(); break; return String.valueOf(result); catch (Exception e) return "Error";
public void clear() memory = 0;
(Logic Engine) import java.math.BigDecimal; import java.math.RoundingMode; import java.util.Stack; public class CalculatorEngine private double memory; private boolean degreeMode = true; scientific calculator source code in java free download