Arrays.binarySearch(long[], int, int, long) in Java

Arrays.binarySearch(long[], int, int, long): This method is available in java.util.Arrays class of Java.

Syntax:

int java.util.Arrays.binarySearch(long[] a, int fromIndex, int toIndex, long key)

This method takes four arguments one of type long array and the one of type long and the other two are of type int as its parameters. This method searches a range of the specified array of longs for the specified value.

Note: The range must be sorted.

Parameters: Four parameters are required for this method.

a: the array to be searched.

fromIndex: the index of the first element (inclusive) to be searched.

toIndex: the index of the last element (exclusive) to be searched.

key: the value to be searched for.

Returns: index of the search key, if it is contained in the array within the specified range; otherwise, (-(insertion point) - 1).

Note: The insertion point is defined as the point at which the key would be inserted into the array: the index of the first element in the range greater than the key, or toIndex if all elements in the range are less than the specified key.

Throws:

1. IllegalArgumentException - if fromIndex > toIndex.

2. ArrayIndexOutOfBoundsException - if fromIndex < 0 or toIndex > a.length

Approach 1: When no exceptions

Java

import java.util.Arrays;

public class ArraysbinarySearchlongRange {
    public static void main(String[] args) {

        // for type long
        long longArray[] = { 17177, 38199, 499999, 
                              5919911, 698191, 70000989 };

        int fromIndex = 2, toIndex = 4;

        long longKey = 499999;

        // to ensure array is sorted
        Arrays.sort(longArray);
        System.out.println(Arrays.binarySearch(longArray,
                    fromIndex, toIndex, longKey));

    }
}

Output:

2

Approach 2: IllegalArgumentException 

Java

import java.util.Arrays;

public class ArraysbinarySearchlongRange {
    public static void main(String[] args) {

        // for type long
        long longArray[] = { 17177, 38199, 499999, 
                                    5919911, 698191, 70000989 };

        int fromIndex = 5, toIndex = 4;

        long longKey = 499999;

        // to ensure array is sorted
        Arrays.sort(longArray);
        System.out.println(Arrays.binarySearch(longArray, 
                                fromIndex, toIndex, longKey));

    }
}

Output:

Exception in thread "main" java.lang.IllegalArgumentException: fromIndex(5) > toIndex(4)
	at java.base/java.util.Arrays.rangeCheck(Arrays.java:718)
	at java.base/java.util.Arrays.binarySearch(Arrays.java:1614)
	

Approach 3: ArrayIndexOutOfBoundsException 

Java

import java.util.Arrays;

public class ArraysbinarySearchlongRange {
    public static void main(String[] args) {

        // for type long
        long longArray[] = { 17177, 38199, 499999, 
                         5919911, 698191, 70000989 };

        int fromIndex = 2, toIndex = 7;

        long longKey = 499999;

        // to ensure array is sorted
        Arrays.sort(longArray);
        System.out.println(Arrays.binarySearch(longArray, 
                   fromIndex, toIndex, longKey));

    }
}

Output:

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: Array index out of range: 7
	at java.base/java.util.Arrays.rangeCheck(Arrays.java:725)
	at java.base/java.util.Arrays.binarySearch(Arrays.java:1614)