package calculator; public class Operators { public static final Operator PLUS = new Operator() { public String symbol() { return "+"; } public int arity() { return 2; } public double evaluate(double[] operandes) { return operandes[0] + operandes[1]; } }; public static final Operator MINUS = new Operator() { public String symbol() { return "minus"; } public int arity() { return 2; } public double evaluate(double[] operandes) { return operandes[0] - operandes[1]; } }; public static final Operator TIMES = new Operator() { public String symbol() { return "*"; } public int arity() { return 2; } public double evaluate(double[] operandes) { return operandes[0] * operandes[1]; } }; public static final Operator DIV = new Operator() { public String symbol() { return "/"; } public int arity() { return 2; } public double evaluate(double[] operandes) { return operandes[0] / operandes[1]; } }; public static final Operator COS = new Operator() { public String symbol() { return "cos"; } public int arity() { return 1; } public double evaluate(double[] operandes) { return Math.cos(operandes[0]); } }; public static final Operator[] FOUR_OPERATIONS = { PLUS, MINUS, TIMES, DIV }; }