binarySearch.py

def binarySearch(arr,target):
    start = 0
    end = len(arr) - 1

    while ( start <= end ):
        mid = start + ( end - start ) // 2
        if (target < arr[mid]):
            end = mid - 1
        elif (target > arr[mid]):
            start = mid + 1
        else:
            return mid
    return -1

def userInput():
    arr = []
    n  = int(input("Enter number of elements: "))
    print("Enter the elements")
    for i in range(0,n):
        element = int(input())
        arr.append(element)
    print(arr)
    target = int(input("Enter the target element: "))

    result = binarySearch(arr,target)
    if(result == -1):
        print("Element not found")
    else:
        print("The element was found at index ", result)

# Tests ('pip install pytest'; run with 'pytest binarySearch.py')
def test_find_element_in_list():
    arr = [11, 12, 22, 25, 34, 64, 90, 91]
    result = binarySearch(arr, 25)
    assert result == 3
    
def test_elem_missing():
    arr = [11, 12, 22, 25, 34, 64, 90, 91]
    result = binarySearch(arr, 16)
    assert result == -1
    
if __name__ == "__main__":
    userInput()