Main.java Source code

Introduction

Here is the source code for Main.java

Source

//package com.java2s;
//License from project: Apache License 

public class Main {
    public static int romanToInteger(java.lang.String romanNumber) {
        int decimal = 0;
        int lastNumber = 0;
        String romanNumeral = romanNumber.toUpperCase();
        /* operation to be performed on upper cases even if user enters roman values in lower case chars */
        for (int x = romanNumeral.length() - 1; x >= 0; x--) {
            char convertToDecimal = romanNumeral.charAt(x);

            switch (convertToDecimal) {
            case 'M':
                decimal = processDecimal(1000, lastNumber, decimal);
                lastNumber = 1000;
                break;

            case 'D':
                decimal = processDecimal(500, lastNumber, decimal);
                lastNumber = 500;
                break;

            case 'C':
                decimal = processDecimal(100, lastNumber, decimal);
                lastNumber = 100;
                break;

            case 'L':
                decimal = processDecimal(50, lastNumber, decimal);
                lastNumber = 50;
                break;

            case 'X':
                decimal = processDecimal(10, lastNumber, decimal);
                lastNumber = 10;
                break;

            case 'V':
                decimal = processDecimal(5, lastNumber, decimal);
                lastNumber = 5;
                break;

            case 'I':
                decimal = processDecimal(1, lastNumber, decimal);
                lastNumber = 1;
                break;
            }
        }
        return decimal;
    }

    public static int processDecimal(int decimal, int lastNumber, int lastDecimal) {
        if (lastNumber > decimal) {
            return lastDecimal - decimal;
        } else {
            return lastDecimal + decimal;
        }
    }
}