# arguments with keywords and variable number of arguments
#
# Matt Bishop, MHI 289I, Fall 2019
#
#
# first, keywords
def pr(first, second):
    print("first =", first, "-- second =", second)

# say what this is
print("Here's how named parameters work")
print("The declaration is 'def pr(first, second)'")

# now we print a couple of these
print("pr(3, 5):", end=' '); pr(3, 5)
print("pr(5, 3):", end=' '); pr(5, 3)

# now name the parameters
print("pr(second=9, first=6):", end=' '); pr(second=9, first=6)

#
# now show default values
#
def pr2(first=5, second=10):
        print("first =", first, "-- second =", second)

# say what this is
print("\nHere's how default parameter values work")
print("The declaration is 'def pr2(first=5, second=10)'")

# show how it works
print("pr2(3, 5):", end=' '); pr2(3, 5)
print("pr2(3):", end=' '); pr2(3)
print("pr2(second=10):", end=' '); pr2(second=20)

#
# and now a variable number of arguments
#
def pr3(*args):
    print(args)

# say what this is
print("\nHere's how a variable number of arguments works")
print("The declaration is 'def pr3(*args)' and it prints the args as a tuple")

# show how it works
print("pr3():", end=' '); pr3()
print("pr3(1):", end=' '); pr3(1)
print("pr3(1, 2):", end=' '); pr3(1, 2)
print("pr3(1, 2, 3):", end=' '); pr3(1, 2, 3)
    
#
# same, but we print them one at a time
#
def pr4(*args):
    # start with the first argument
    n = 0
    # walk the argument list
    for i in args:
        # first argument is numbered 1, then successive
        # arguments are numbered 2, 3, ...
        n += 1
        print("\targ #%d:" % n, i)

print("\nThe declaration is 'def pr4(*args)' and it prints the args one at a time")

# show how it works
print("pr4():", end=' '); pr4()
print("pr4('a'):"); pr4('a')
print("pr4('b', 'c'):"); pr4('b', 'c')
print("pr4('d', 'e', 'f'):"); pr4('d', 'e', 'f')