{"id":1283,"date":"2016-07-16T05:58:43","date_gmt":"2016-07-16T05:58:43","guid":{"rendered":"http:\/\/www.testingdocs.com\/questions\/?p=1283"},"modified":"2024-08-09T03:50:08","modified_gmt":"2024-08-09T03:50:08","slug":"write-a-java-program-for-binary-search","status":"publish","type":"post","link":"https:\/\/www.testingdocs.com\/questions\/write-a-java-program-for-binary-search\/","title":{"rendered":"Write a Java Program for Binary Search? [ 2024 ]"},"content":{"rendered":"

Write a Java Program for Binary Search?<\/h2>\n

In this tutorial, we will write a Java program to implement Binary Search.\u00a0BS<\/b>\u00a0is faster than sequential search<\/b>. The requirement for BS\u00a0is that the array should be sorted in a particular order before searching.<\/p>\n

Divide and Conquer<\/h3>\n

Assume that searchItem that needs to be searched and array sorted in ascending order. We will find the middle of the array and compare with searchItem.<\/p>\n

If searchItem is greater than the middle item of the array then search<\/b> the right half of the array. If the searchItem is less than the middle item, then search<\/b> the left half array.<\/p>\n

Flow Chart<\/strong><\/h3>\n

\"\"<\/p>\n

 <\/p>\n

Binary Search Java program<\/strong><\/h3>\n
import java.util.Arrays;\r\nimport java.util.InputMismatchException;\r\nimport java.util.Scanner;\r\n\r\npublic class BinarySearchExample {\r\n    public static void main(String[] args) {\r\n        int n;\r\n        Scanner input = null;\r\n        int[] a = null;\r\n        int searchItem,low,high;\r\n        try {\r\n            input=new Scanner(System.in);\r\n            System.out.println(\"Enter size of the array:\");\r\n            n= input.nextInt();\r\n\r\n            if(n > 0) {\r\n                a=new int[n];\r\n                System.out.println(\"Enter array elements:\");\r\n                for (int i = 0; i < n; i++) {\r\n                    a[i] = input.nextInt();\r\n                }\r\n            }else{\r\n                System.out.println(\"Enter positive number.\");\r\n                System.exit(0);\r\n            }\r\n\r\n            System.out.println(\"Input Unsorted Array is:\");\r\n            printArray(a);\r\n\r\n            System.out.println(\"Enter the search item\");\r\n            searchItem =input.nextInt();\r\n            Arrays.sort(a);\r\n\r\n            System.out.println(\"Input Sorted Array is:\");\r\n            printArray(a);\r\n\r\n            System.out.println(\"Performing Binary search for:\"+ searchItem);\r\n\r\n            low=0;\r\n            high=a.length-1;\r\n\r\n            while(high >= low) {\r\n                int mid = (high+low)\/2;\r\n                if(a[mid] == searchItem){\r\n                    System.out.println(\"Item found at:\" + mid );\r\n                    System.exit(0);\r\n                }\r\n\r\n                else if(a[mid] < searchItem) {\r\n                    low = mid + 1;\r\n                }\r\n                else {\r\n                    high = mid - 1;\r\n                }\r\n            }\r\n\r\n        }catch (InputMismatchException ime) {\r\n            System.out.println(\"Not a valid input\");\r\n        }\r\n        catch (Exception e) {\r\n            e.printStackTrace();\r\n        } finally\r\n        {\r\n            if(input!=null)\r\n            {input.close();}\r\n        }\r\n    }\r\n\r\n    private static void printArray(int[] a){\r\n        for (int aA : a) {\r\n            System.out.print(\"[ \" + aA + \" ]\");\r\n        }\r\n        System.out.println( \"\");\r\n    }\r\n\r\n}<\/pre>\n
 <\/p>\n
Run output of the program<\/strong><\/h3>\n
Save the program in the IDE and execute the program.<\/p>\n
User Input for the program:<\/p>\n
Enter the size of the array. The program prompts for array elements. Enter the array elements.<\/p>\n
The program then prompts the user to enter the search item.<\/p>\n
\"Binary<\/p>\n
Enter size of the array:
\n7
\nEnter array elements:
\n23
\n56
\n9
\n103
\n77
\n99
\n14
\nInput Unsorted Array is:
\n[ 23 ][ 56 ][ 9 ][ 103 ][ 77 ][ 99 ][ 14 ]
\nEnter the search<\/b> item
\n77
\nInput Sorted Array is:
\n[ 9 ][ 14 ][ 23 ][ 56 ][ 77 ][ 99 ][ 103 ]
\nPerforming Binary<\/b> search<\/b> for:77
\nItem found at:4<\/p>\n
Java Tutorials<\/h2>\n
Java Tutorial on this website:<\/p>\n