''' Purpose: try out functions
'''
import harb                             # import access to module harb

n1, n2 =  3, 14                         # get some values for function exploration
n3, n4 = 15, 92
n5, n6 = -6, 53

# Remember that sum had parameters a and b so when we pass in n1 and n2 as ARGUMENTS,
# we gave it the explicit values so that the function can use those values.
# So parameters are basically filled in by arguments.
# a gets 3 (n1) and b gets 14 (n2)!

# We assigned the variable t1 the function invocation of sum(n1,n2)
# whatever is RETURNED by sum is stored in t1. sum(n1,n2) returns the sum of arguments
# n1 and n2 which in this first case would be 3+14 = 17 so t1 = 17.

# These function invocations are pass by value (copies of values).
# n1 and n2 are not changed! We are just passing copies of those into
# the function call to start up the function.

# Function call: module_name.function_name(arguments)
# Make sure you have your modules and the programs that import/use those modules
# in the same folder!
# You need to have the same number of arguments to fill in the same number of parameters.
# Here, we pass in two arguments (n1 and n2) to fill in two parameters (a and b).
# t0 = harb.sum(3,4,5) - Too many arguments!

t1 = harb.sum( n1, n2 )                 # invoke harb.sum() with arguments n1 and n2
                                        # return value used to set t1 !!!

t2 = harb.sum( n3, n4 )                 # invoke harb.sum() with arguments n3 and n4
                                        # return value used to set t2 !!!

print( "sum(", n1, ",", n2, "):", t1 )
print( "sum(", n3, ",", n4, "):", t2 )

print()

i1 = harb.negate( n5 )                  # invoke harb.negate() with argument n5
                                        # return value used to set i1

i2 = harb.negate( n6 )                  # invoke harb.negate() with argument n6
                                        # return value used to set i2

print( "inverse(", n5, "):", i1 )
print( "inverse(", n6, "):", i2 )