maniish-jaiin

   public double evaluate(String s) {
        String[] elements = getStringArray(s);
        Stack<Double> numbers = new Stack();
        double result = 0.0;
        for (String c : elements) {
            switch (c) {
                case "+": {
                    result = numbers.push(numbers.pop() + numbers.pop());
                    break;
                }

maniish-jaiin

@Test
public void evaluateWhenAllOperatorAreFound() {
    ReversePolishNotation rpn = new ReversePolishNotation();
    double result = rpn.evaluate("10 6 9 3 + -11 * / * 17 + 5 +");
    assertEquals(21.5, result, 0.1);
}

maniish-jaiin

public double evaluate(String s) {
    String[] elements = getStringArray(s);
    Stack<Double> numbers = new Stack();
    double result = 0.0;
    for (String c : elements) {
        switch (c) {
            case "+":
                result = numbers.push(numbers.pop() + numbers.pop());
                break;
            case "-":

maniish-jaiin

@Test
public void addNumbersWhenMinusOperatorIsFound() {
    ReversePolishNotation rpn = new ReversePolishNotation();
    double result = rpn.evaluate("5 5 2 + -");
    assertEquals(2.0, result, 0.1);
}

@Test
public void addNumbersWhenMultiplyOperatorIsFound() {
    ReversePolishNotation rpn = new ReversePolishNotation();

maniish-jaiin

public double evaluate(String s) {
        String[] elements = getStringArray(s);
        Stack<Double> numbers = new Stack();
        double result = 0.0;
        for (int i = 0; i < elements.length; i++) {
            String c = elements[i];
            if (c.equals("+") && i >= 2) {
                result = numbers.push(numbers.pop() + numbers.pop());
            } else {
                numbers.push(Double.parseDouble(c));

maniish-jaiin

@Test
public void addNumbersWhenMultiplePlusOperatorIsFound() {
    ReversePolishNotation rpn = new ReversePolishNotation();
    double result = rpn.evaluate("5 5 2 + +");
    assertEquals(12.0, result, 0.1);
}

maniish-jaiin

public double evaluate(String s) {
        String[] elements = getStringArray(s);
        double result = 0.0;
        for (int i = 0; i < elements.length; i++) {
            String c = elements[i];
            if (c.equals("+") && i >= 2) {
                result = parseDouble(elements[i - 1]) + parseDouble(elements[i - 2]);
            }
        }
        return result;

maniish-jaiin

@Test
public void addNumbersWhenPlusOperatorIsFound() {
        ReversePolishNotation rpn = new ReversePolishNotation();
        double result = rpn.evaluate("3 4 +");
        assertEquals(7.0, result, 0.1);
    }

maniish-jaiin

public void addNumbersWhenPlusOperatorIsFound() {
        ReversePolishNotation rpn = new ReversePolishNotation();
        double result = rpn.evaluate("5 5 +");
        assertEquals(10.0, result, 0.1);
    }

maniish-jaiin

public String[] getStringArray(String s) {
        return s.split(" ");
    }