Java Decimal From toDecimal(String number)

Description

to Decimal

License

Apache License

Declaration

public static int toDecimal(String number) 

Method Source Code

//package com.java2s;
/**/*  w  w  w  . j av  a  2s .  co  m*/
 *
 * maer - Solutions to problems of Project Euler
 * Copyright (C) 2011, Sandeep Gupta
 * http://www.sangupta.com/projects/maer
 *
 * The file is licensed under the the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

public class Main {
    public static int toDecimal(String number) {
        number = number.toUpperCase();

        int decimal = 0;
        char lastChar = 0;
        for (int index = 0; index < number.length(); index++) {
            char c = number.charAt(index);
            switch (c) {
            case 'I':
                decimal += 1;
                break;

            case 'V':
                if (lastChar != 'I') {
                    decimal += 5;
                } else {
                    decimal += 3;
                }
                break;

            case 'X':
                if (lastChar != 'I') {
                    decimal += 10;
                } else {
                    decimal += 98;
                }
                break;

            case 'L':
                if (lastChar != 'X') {
                    decimal += 50;
                } else {
                    decimal += 30;
                }
                break;

            case 'C':
                if (lastChar != 'X') {
                    decimal += 100;
                } else {
                    decimal += 80;
                }
                break;

            case 'D':
                if (lastChar != 'C') {
                    decimal += 500;
                } else {
                    decimal += 300;
                }
                break;

            case 'M':
                if (lastChar != 'C') {
                    decimal += 1000;
                } else {
                    decimal += 800;
                }
                break;
            }
            lastChar = c;
        }

        return decimal;
    }
}

Related

1. toDecimal(final String intValue)
2. toDecimal(float value)
3. toDecimal(int value, byte[] buffer, int offset, int length, int itemLength, boolean packed)
4. toDecimal(long val, int places)
5. toDecimal(String coord)