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

# In[6]:


# continuing section 2.7
# FACTS:
# 1. operation on two integers --> generally gives an integer
# Check this:
print("1+2=",1+2)
print(type(1+2))
# 2. operation on two floats --> will give a float
print("1.0+2.0=",1.0+2.0)
print(type(1.0+2.0))
# 3. operation containing mixed (int and float) --> will give float
x=1
print("x=1 and x+2.0=",x+2.0)
print(type(x+2.0))
print("the type of x is",type(x))
#
# If you need to force a variable conversion, you can
# use int() and float() to do it.
print("x=",x)
print("type(x)=",type(x))
print("type(float(x))=",type(float(x)))


# In[19]:


# Section 2.8 -- More about output
# We know already how the following behaves:
print('A')
print('B')
print('C')
# Of course: it prints over three lines.
# This is because the "default" "end line" character
# is the so-called "newline character" 
# read more: https://en.wikipedia.org/wiki/Newline
#
print('--------------------')
#
# We can change the endline character:
# it is just an "option" for the print function
# the following command behaves same as print('A'):
print('A',end="\n")
# the following appends abracadabra to the end of the print
# WITH NO SPACE OR NEW LINE
print('B',end="abracadabra")
# the following appends a space after it prints the character
# C but nothing else
print('C',end=" ")
print('more stuff')
# see print documentation: https://docs.python.org/3/library/functions.html#print
# test the sep option
# compare
printthis="stuff stuff"
print('a',printthis,'b',printthis)
print('a',printthis,'b',printthis,sep='17')


# In[23]:


# Section 2.9 -- named constants
# Imagine scenario where you are hired by a bank to code
# you come across the following code:
balance = 15.00
feedividend=balance*0.069
# here: the number 0.069 is a "magic number" in that it 
#       appears to be important to the code functioning 
#       properly, but its real purpose is not clear
#
# One way to fix the issue of not knowing what this number
# is for is to use comments liberally!!!
#
# Another way -- use a "named constant"
INTEREST_RATE=0.069
feedividend=balance*INTEREST_RATE
costowed=balance+50*INTEREST_RATE

# Example of a magic number
# In Quake III Arena, the coders needed to compute
# 1/sqrt(x), where x was some number.
#
# At this time, computing 1/sqrt(x) was expensive for the
# computer -- doing so the "old way" might cause slowdowns
# in the graphic processing of the map.
#
# How they did it:
# shift right operation: shifts the binary bits to right by 1
print("11>>1=",11>>1)
# 1. Took a 32-bit float number and shifted right
# 2. subtract the shifted number from the hexadecimal number
#    0x5F3759DF which encodes the number 1597463007 in hex
# 3. run one instance of Newton's method to increase precision
#
# the magic number was 0x5F3759DF


# In[24]:


#
# this code doesn't run in Jupyter notebook
# RUN IT HERE INSTEAD: https://repl.it/languages/tkinter
#
# Here we finally learn hwo to 
# import a package
import time
import turtle
# this shows the turtle
turtle.showturtle()
print("starting position=",turtle.pos())
# this halts for 5 seconds before doing next thing
time.sleep(2)
# this one moves the turtle forward 30 pixels
turtle.forward(30)
print("after moving forward 30",turtle.pos())
time.sleep(2)
turtle.forward(10)
print("after moving forward another 10",turtle.pos())
time.sleep(2)
# rotates the turtle to the right 
# by the given number of degrees
turtle.right(45)
time.sleep(2)
turtle.forward(50)
print("after moving forward another 50",turtle.pos())
time.sleep(2)
# we can set a "heading" -- an angle for which 
# it should point
# we measure angles starting at 0 deg to 360 deg in a
# counterclockwise motion
#
#
# we force an angle for turtle to point using the following:
turtle.setheading(190)
time.sleep(2)
turtle.forward(100)
print("after moving forward another 100",turtle.pos())
time.sleep(2)
# can change the turtle's position to anywhere
# we want
#
# can clear and reset the turtle back to default:
turtle.reset()
turtle.setheading(180)
turtle.forward(100)
time.sleep(2)
turtle.setheading(0)
turtle.forward(50)
time.sleep(2)
turtle.setheading(270)
turtle.forward(200)
time.sleep(5)