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Author: samraj-freak

BinarySearch.java

@@ -0,0 +1,65 @@
+import java.util.Scanner;
+
+/*
+ * Java Program to implement binary search without using recursion
+ */
+public class BinarySearch {
+
+    public static void main(String[] args) {
+
+        Scanner commandReader = new Scanner(System.in);
+        System.out.println("Welcome to Java Program to perform 
+                               binary search on int array");
+        System.out.println("Enter total number of elements : ");
+        int length = commandReader.nextInt();
+        int[] input = new int[length];
+
+        System.out.printf("Enter %d integers %n", length);
+        for (int i = 0; i < length; i++) {
+            input[i] = commandReader.nextInt();
+        }
+
+        System.out.println("Please enter number to be searched in array 
+                                    (sorted order)");
+        int key = commandReader.nextInt();
+
+        int index = performBinarySearch(input, key);
+
+        if (index == -1) {
+            System.out.printf("Sorry, %d is not found in array %n", key);
+        } else {
+            System.out.printf("%d is found in array at index %d %n", key,
+                                                         index);
+        }
+
+        commandReader.close();
+
+    }
+
+    /**
+     * Java method to perform binary search. It accept an integer array and a
+     * number and return the index of number in the array. If number doesn't
+     * exists in array then it return -1
+     *
+     * @param input
+     * @param number
+     * @return index of given number in array or -1 if not found
+     */
+    public static int performBinarySearch(int[] input, int number) {
+        int low = 0;
+        int high = input.length - 1;
+
+        while (high >= low) {
+            int middle = (low + high) / 2;
+            if (input[middle] == number) {
+                return middle;
+            } else if (input[middle] < number) {
+                low = middle + 1;
+            } else if (input[middle] > number) {
+                high = middle - 1;
+            }
+        }
+        return -1;
+    }
+
+}