Tag: Remove

I have to get rid of if, else statements from my code because it's a smell. I know that you can implement the status pattern to remove it. However, in my code, I check that the string input is a specific operator, and then execute the steps on a stack. How would I do that? Should I create different states that also perform the math and stack operations? My main problem is that I do not understand how to implement it without using an if statement. For example, if I encounter an operator, I want to do something, but since there are a number of different operators, I need to check that the input is a "+" to do the code necessary for that section.

Here is my code:

package src;

import java.util.Arrays;
import java.util.List;
import java.util.Stack;

public class RPNCalculator {

    public int solveEquation(final String input) {
        final Stack operands = new Stack();

        List tokenizedInput = Arrays.asList(input.split(" "));

        for (String currentToken : tokenizedInput) {
            try {
                int inputAsInt = Integer.parseInt(currentToken);
                operands.push(inputAsInt);
                continue; //
            } catch (NumberFormatException exception) {
                // do nothing, just continue
            }

            if (currentToken.contains("+")) {
                int total = operands.pop() + operands.pop();
                operands.push(total);

            } else if (currentToken.contains("-")) {
                int secondNum = operands.pop();
                int total = operands.pop() - secondNum;
                operands.push(total);

            } else if (currentToken.contains("*")) {
                int total = operands.pop() * operands.pop();
                operands.push(total);

            } else if (currentToken.contains("/")) {
                int secondNum = operands.pop();
                int total = operands.pop() / secondNum;
                operands.push(total);

            }