def largest_elem(int_list):
    """
    Returns the largest element in int_list
    int_list: list of int, length >= 1
    """   
    k = 1
    my_max = int_list[0]

    # INV: max is largest int in int_list[0...k-1]
    while  k < len(int_list):
        my_max = max(my_max, int_list[k])
        k = k + 1

    # POST: max = largest int in int_list[0..len(int_list)–1]
    return my_max

def print_results(alist, the_max):
    print("The largest element in "+str(alist)+" is "+str(the_max))

list1 = [2,6,5,8,2,-5]
big1 = largest_elem(list1)
print_results(list1, big1)

list2 = [20,6,15,-8,2,-5]
big2 = largest_elem(list2)
print_results(list2, big2)