binarySearch_in_C#.cs

Searching/Binary-Search/binarySearch.cs

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+// C# implementation of recursive Binary Search
+using System;
+
+class GFG {
+	// Returns index of x if it is present in
+	// arr[l..r], else return -1
+	static int binarySearch(int[] arr, int l, int r, int x)
+	{
+		if (r >= l) {
+			int mid = l + (r - l) / 2;
+
+			// If the element is present at the
+			// middle itself
+			if (arr[mid] == x)
+				return mid;
+
+			// If element is smaller than mid, then
+			// it can only be present in left subarray
+			if (arr[mid] > x)
+				return binarySearch(arr, l, mid - 1, x);
+
+			// Else the element can only be present
+			// in right subarray
+			return binarySearch(arr, mid + 1, r, x);
+		}
+
+		// We reach here when element is not present
+		// in array
+		return -1;
+	}
+
+	// Driver method to test above
+	public static void Main()
+	{
+
+		int[] arr = { 2, 3, 4, 10, 40 };
+		int n = arr.Length;
+		int x = 10;
+
+		int result = binarySearch(arr, 0, n - 1, x);
+
+		if (result == -1)
+			Console.WriteLine("Element not present");
+		else
+			Console.WriteLine("Element found at index "
+							+ result);
+	}
+}
+
+// This code is contributed by Ashraf