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

# In[17]:


# Section 3.1 - "if statements"
#
# an if statement checks if something holds
# 1. if the something holds, then it does something
# 2. if the something doesn't hold, then it doesn't do anything
#
#
# Syntax
# if condition:
#     do a thing
#     do another thing
#     bla bla bla
# code here, is not part of the "do a thing" portion
#
# Example from board:
# 
# if it is cold:
#     put on a jacket
# go outside
#
# "Relational operators"
# Symbol     Meaning
#   >        greater than 
#   <        less than
#  >=        greater than or equal to
#  <=        less than or equal to
#  ==        equality (as in math class)
#  !=        not equal (as in math class)

# Example -- the following code gives an error because "x=5"
#            is NOT the "relational operator" for checking
#            equality of two statements
#            "=" is variable assignment, "==" is to check equality
#x=5
#if x=5:
#    print("x is five!!!!")
#
# Expression       Meaning
#   x > y          "Is x greater than y?"
#   x < y          "Is y less than x?"
#   x <= y         "Is x less than or equal to y?"
#   x >= y         "Is x greater than or equal to y?"
#   x==y           "Is x equal (mathematically) to y?"
#   x!=y           "Is x NOT equal (mathematically) to y?"
#
# 

# Test these operations
x=1
y=0
print("We set x=1 and y=0")
print("x>=y is",x>=y) # this gives "True" as an output
print("x==y is",x==y) # this gives "False"
print("x!=y is",x!=y) # this gives "True"
z=1
print("Now we set z=1")
print("x==z is",x==z)

# Notice something interesting:
print("The type of x>y is",type(x>y))
# We got that the type was "bool". This happens for any relational operator:
print("The type of x!=y is",type(x!=y))
print("The type of x==y is",type(x==y))
# bool is short of "boolean" which is named after logician
# George Boole who investigated "boolean algebra" in the 1800s among other things
#
#
#


# In[33]:


# Write a program to take three test scores, report the average, and then
# give a response to the user related to the value of the average. 
#
# Maybe: if average < 60 tell the user "Your grade is not so good."
#        if average > 90 tell the user "Your grade is great!"
# The 60 and the 90 are magic numbers... we should define them with named constants
#
# Alteration from a class question: can we give a message if the score
#             is between 60 and 90?
LOW_AVG=60
HIGH_AVG=90

# obtain three test scores from the user:
score1=float(input("What was the grade on exam 1?"))
score2=float(input("What was the grade on exam 2?"))
score3=float(input("What was the grade on exam 3?"))

# compute the average
average=(score1+score2+score3)/3
print("Your average score was",average,"percent.")

# make further responses for extreme scores
if average < LOW_AVG:
    print("Your grade is not so good.")
if average > HIGH_AVG:
    print("Your grade is great!")
#####
    #extra code from the question in class
#####
#####
if average >= LOW_AVG:
    if average<=HIGH_AVG:
        print("Your grade is... ok.")
# note -- this can be done in one line with a "logical operator"
# "AND" which would be written as if average >= LOW_AVG and average <= HIGH_AVG:
#####
#####
print("Please record your score for future use.")


# ###