public static void main(String args[]) {
String str1 = "a+b";
String str2 = "a-b";
Map<String, Integer> map = new HashMap<String, Integer>(5);
map.put("a", 3);
map.put("b", 4);
Calculator cal = new Calculator(str2);
System.out.println(str2 + cal.run(map));
}
public static void main(String[] args) {
Calculator calculator = new Calculator();
calculator.addOperation(new Plus(calculator, "+"));
calculator.run();
}
