// Controller Method
private void calculator(String operator) throws Exception {
if (isUnary(operator)) {
float op1 = Float.parseFloat(stack.pop());
UnaryOperator operation = Unary.getOperator(operator);
float result = operation.getResult(op1);
stack.push(String.valueOf(result));
} else if (isBinary(operator)) {
float op2 = Float.parseFloat(stack.pop());
float op1 = Float.parseFloat(stack.pop());
BinaryOperator operation = Binary.getOperator(operator);
float result = operation.getResult(op1, op2);
stack.push(String.valueOf(result));
} else throw new Exception("Operator not Supported!");
}
