#!/usr/bin/env python
# coding: utf-8

# In[1]:


# Section 5.5 continued
# Keyword arguments
# You've done this before: 
print("abc","def","ghi",sep='XYZ') # here -- the code
#                                  # sep='XYZ' is specifying
#                                  # a keyword parameter
# Example program with simple interest
# FYI: simple interest=int_rate*principal*periods
def main():
    show_interest(rate=0.01,periods=10,principal=10000)
    #show_interest(0.01,10,10000)
def show_interest(principal, rate, periods):
    interest=rate*principal*periods
    print("The rate is",rate)
    print("The simple interest will be $",format(interest,'.2f'),sep='')
main()


# In[4]:


# Section 5.6 -- global variables and global constants
# Definition: A global variable can be accessed by any function.
# Example
my_value=10
def show_value():
    print(my_value)
show_value()

# In the previous example -- a global variable was defined
# outside of the function and then used inside of the 
# function.
#
# Now we will define a global variable from within a function.
# Generally: this is bad behavior -- avoid as much as possible
#
def main():
    global number # avoid this when you can -- usually you can
    number=int(input("Give me an integer."))
    show_number()
def show_number():
    print("Your number is",number)
main()
print(number) # this is surprising, because the number
#             # variable was NOT destroyed when the main()
#             # function terminated -- this is what the keyword
#             # global made happen
#
# why avoid this: makes debugging a nightmare


# In[8]:


# Section 5.7 - value-returning functions
# idea: A value-returning function "returns" a value when it terminates
# so far -- all of our functions terminate without "returning" a value
# this is different than "printing" something
#
# Importing packages -- we've done this before: turtle, time
# Look at the random package
#
#
# Import the random module:
import random
#
# Generally: a module is thought of as a "black box" meaning
# you feed functions inputs and they give outputs, but you
# don't really think too much about "how" they do it.
#
#
#
# look at some functions in the random package
# Display a "random" integer between 1 and 10
def main():
    number=random.randint(1,10)
    print("Your random number is",number)
main()
main()
main()
main()
main()
main()
main()
main()
main()
main()
main()
main()
main()
main()
main()
main()


# In[10]:


# Die roller program
# Generate two random numbers between 1 and 6
# User should be asked if they want to roll again
import random
MIN=1
MAX=6

def main():
    # loop control -- use a control variable
    go_again='y'
    while go_again=='y':
        print("Rolling...")
        print("First die roll is",random.randint(MIN,MAX))
        print("Second die roll is",random.randint(MIN,MAX))
        go_again=input("Write y to roll again, n to stop.")
main()


# In[27]:


# Some more funcitons in random module
import random
#random.randrange(#) # this picks a random number between 0 and #-1
random.randrange(7) 
#random.randrange(A,B) # pick random between A and B-1
#random.randrange(A,B,C) # pick random among A, A+C, A+2C, ..., A+kC where A+kC < B < A+(k-1)C
#
#Example: generate a random even number between 0 and 10
#random.seed(10) # all randomness depends on the seed
print(random.randrange(0,11,2))
print(random.randrange(0,11,2))
print(random.randrange(0,11,2))
print(random.randrange(0,11,2))
print(random.randrange(0,11,2))
print(random.randrange(0,11,2))
print(random.randrange(0,11,2))
print(random.randrange(0,11,2))
# random function
print("this gives a number x such that 0<=x<1",random.random())
# uniform function
print("this gives a number x such that A<=x<B",random.uniform(10,15))


# In[33]:


# Section 5.8 -- writing a value-returning function
# Syntax
#
# def function(parameters):
#     stuff
#     stuff
#     return expression
#
#Compare two functions
def add_two(num1,num2):
    result=num1+num2
    return float(result)
def add_two_print(num1,num2):
    result=num1+num2
    print(result)
var1=add_two(1,2)
var2=add_two_print(2,5)
print("var1 is",var1)
print("var2 is",var2)
print(type(var1))
print(type(var2))