# Returns index of x in arr if present, else -1

def binary_search(arr, low, high, x):

if high >= low:

mid = (high + low) // 2

# If 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

elif arr[mid] > x:

return binary_search(arr, low, mid - 1, x)

# Else the element can only be present in right subarray

else:

return binary_search(arr, mid + 1, high, x)

else:

# Element is not present in the array

return -1

arr = [ 2, 3, 4, 10, 40 ]

x = 10

result = binary_search(arr, 0, len(arr)-1, x)

if result != -1:

print("Element is present at index", str(result))

else:

print("Element is not present