Java tutorial
//package com.java2s; /** * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under 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 { private static int parse(char[] chars, int offset, int len, int radix, boolean negative) throws NumberFormatException { int max = Integer.MIN_VALUE / radix; int result = 0; for (int i = 0; i < len; i++) { int digit = Character.digit(chars[i + offset], radix); if (digit == -1) { throw new NumberFormatException("Unable to parse"); } if (max > result) { throw new NumberFormatException("Unable to parse"); } int next = result * radix - digit; if (next > result) { throw new NumberFormatException("Unable to parse"); } result = next; } /*while (offset < len) { }*/ if (!negative) { result = -result; if (result < 0) { throw new NumberFormatException("Unable to parse"); } } return result; } }