Sentinel Linear Search

# sentinel_linear_search.py
#   This program uses a linear search of an array of size n for
#   value x but unlike its predecessor linear_search.py it utilizes
#   a sentinel value in the arrays last index as a placeholder
#   ensuring that only one check takes place becuase you will not be
#   checkinf for the array length, just the search term x
#   This algorithm is more efficient than either linear_search.py or
#   better_linear_search.py.
# by: Scott Gordon

things = ["bike", "house", "cat", "computer", "hammer"]


def linear_search(array, n, x):
    last = array[n-1]
    array[n-1] = x
    i = 1
    while array[i] != x:
        i += 1
    array[n-1] = last
    if (i < n-1) or (array[n-1] == x): 
        return i
    else:
        return "Not found!"


print(linear_search(things, 5, "cat"))  # prints the index of "cat" which is 2
# prints the index of "hammer" which is 4
print(linear_search(things, 5, "hammer"))
print(linear_search(things, 5, "pasta"))  # prints Not found
print(linear_search(things, 5, "junk"))  # prints Not found