# File: args2.py
# Program to demonstrate how functions handle variables
#
# Matt Bishop, MHI 289I, Winter 2018
#

#
# this one shows passing parameters
# it just prints the 3 arguments
def func1(a, b, c):
    print "Argument #1:", a
    print "Argument #2:", b
    print "Argument #3:", c
    y = int(b)

#
# this one defines a local variable, x
# and assigns a value to it
def func2():
    x = 9
    print "func2: x =", x
    
#
# this one changes the value of a parameter
def func3(y):
    print "func3: y =", y
    y = 3456
    print "func3: y =", y
    
#
# this one changes the value of a parameter
def func4(y):
    print "func4: y =", y[0]
    y[0] = 3456
    print "func4: y =", y[0]
    
#
# the main program
#
# first, show how arguments are passed
func1(7, "3", -3.14159)
# now, show how local variables doesn't
# affect variables in the caller
x = 6
print "main: x =", x
func2()
print "main: x =", x
# show how changing parameters
# doesn't affect variables in the caller
y = 21
print "main: y =", y
func3(y)
print "main: y =", y
# finally, show how changing parameters
# that are list elements does affect
# variables in the caller
y = [ 21 ]
print "main: y =", y
func4(y)
print "main: y =", y