Perform a linear search for an integer in a given array. - Java Collection Framework

Java examples for Collection Framework:Array Algorithm

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Description

Perform a linear search for an integer in a given array.

Demo Code

/*//from  ww w  .  j av  a  2 s  . c  om
 * Copyright (C) 2013 Marten Gajda <marten@dmfs.org>
 *
 * Licensed 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.
 * 
 */
//package com.java2s;

public class Main {
    /**
     * Perform a linear search for an integer in a given array. For small fields a linear search can be faster than a binary search. So use this if you know
     * your field contains only few entries.
     * 
     * @param array
     *            The array to search (the hay stack). Must not be <code>null</code>!
     * @param i
     *            The value to search for (the needle).
     * @return the position of the value in the array or <code>-1</code> if the value has not been found.
     */
    public static int linearSearch(int[] array, int i) {
        for (int c = 0, len = array.length; c < len; ++c) {
            if (array[c] == i) {
                return c;
            }
        }
        return -1;
    }

    /**
     * Perform a linear search for a long in a given array. For small fields a linear search can be faster than a binary search. So use this if you know your
     * field contains only few entries.
     * 
     * @param array
     *            The array to search (the hay stack). Must not be <code>null</code>!
     * @param l
     *            The value to search for (the needle).
     * @return the position of the value in the array or <code>-1</code> if the value has not been found.
     */
    public static int linearSearch(long[] array, long l) {
        return linearSearch(array, 0, array.length, l);
    }

    /**
     * Perform a linear search for a long in a given array. For small fields a linear search can be faster than a binary search. So use this if you know your
     * field contains only few entries.
     * 
     * @param array
     *            The array to search (the hay stack). Must not be <code>null</code>!
     * @param start
     *            the inclusive start position of the range to search
     * @param end
     *            the exclusive end position of the range to search
     * @param l
     *            The value to search for (the needle).
     * @return the position of the value in the array or <code>-1</code> if the value has not been found.
     */
    public static int linearSearch(long[] array, int start, int end, long l) {
        for (int c = start; c < end; ++c) {
            if (array[c] == l) {
                return c;
            }
        }
        return -1;
    }
}

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