# Lab_7_Exercise_1_Problem_1_a.py
# a.k.a. Multiplication_by_Recursive_Addition.py
#
# This program multiplies x by y by adding x y times recursively.
#
# Anne Lavergne
# March 2017


def multiply( x, y ):
    """ Recursively implements the multiplication x * y using addition.
        Parameters: x, y - x is never mutated.
        Returned value: product i.e., x * y
    """
    if y == 0 : result = 0  # Base case 1
    elif y == 1 : result = x  # Base case 2
    else : result = x + multiply( x, y - 1 )  # Recursive case
    return result


# Main part of the program

# Get user input
operandList = input("Please, enter the two numbers you wish to multiply: ").split()

# I am assuming that user input is valid
# operand1 -> equationList[0]
# operand2 -> equationList[1]
# Future modification: validation user input

operandList = [ int(operandList[i]) for i in range(len(operandList)) ]
# x -> operandList[0]
# y -> operandList[1]

print("{} * {} = {} ".format(operandList[0], operandList[1], multiply(operandList[0], operandList[1])))
print("----")