Added binary search in swift

Swift/Algorithms/binary_search.swift

@@ -0,0 +1,30 @@
+// Binary search | Swift
+func binarySearch(in numbers: [Int], for value: Int) -> Int?
+{
+    var left = 0
+    var right = numbers.count - 1
+
+    while left <= right {
+
+        let middle = Int(floor(Double(left + right) / 2.0))
+
+        if numbers[middle] < value {
+            left = middle + 1
+        } else if numbers[middle] > value {
+            right = middle - 1
+        } else {
+            return middle
+        }
+    }
+
+    return nil
+}
+// Driver code
+let numbers = [2, 3, 5, 7, 11, 13, 17, 19, 23, 29]
+let value = 17
+
+if let index = binarySearch(in: numbers, for: value) {
+    print("Found \(value) at index \(index)")
+} else {
+    print("Did not find \(value)")
+}