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

# <h1><center>cs1001.py , Tel Aviv University, Fall 2017-2018</center></h1>
# <img src="http://www.pngall.com/wp-content/uploads/2016/05/Python-Logo-PNG-Image-180x180.png" width=50/>
# 

# # Recitation 1

# We have seen some basic types and operations, conversion functions, the function input and several structures that Python has to offer: if-else, while loops, and for loops. We had also solved an excercise of counting the number of zeros in a number inputted by the user.
# 
# #### Takeaways:
# 
# <ol>
#   <li>Try to "play" with types, operators, structures, and built-in functions in order to understand the basics of Python.</li>
#   <li>To tackle programming exercises, try to first imagine what you want the solution to do intuitively and then find ways to implement it.</li>
#   <li>Read the instructions for the submission of home assignments and submit your code as a .py file.</li>
#   <li>Test your code before you submit.</li>
# </ol>
# 

# ## Types and Variables

# In[23]:


x = 3
y = 3.14
c = "intro2CS"
b = True
type(x), type(y), type(c), type(b)


# ## Operators

# In[4]:


x + y


# In[5]:


c + "amir"


# In[63]:


"4" + "5"3 < 4 and 3==4


# In[6]:


c * "amir"


# In[7]:


c * 2


# In[8]:


c * 2.5


# In[9]:


c * 2.0


# In[10]:


2 + 2.0


# In[11]:


2**0.5


# In[12]:


2**2.0 


# In[13]:


2.0**2


# In[14]:


10%2


# In[15]:


109%10


# In[17]:


9//2 # rounding down


# In[18]:


3 < 4


# In[19]:


3 == 4


# In[20]:


3 != 4


# In[21]:


True and False


# In[64]:


3 < 4 and 3==4


# In[59]:


-2%10


# In[24]:


type(3 < 4)


# ## Conversion Functions

# In[25]:


int("4")


# In[26]:


int(4.0)


# In[27]:


int("4.0")


# In[65]:


int(4.99) # int() always rounds down


# In[28]:


float(4)


# In[29]:


float("3.14")


# In[30]:


float("3")


# In[31]:


str(43)


# In[32]:


str(True)


# In[35]:


course = "intro" + str(2) + "cs"
course


# ## If-else structure

# In[36]:


today = "Monday"
strike = "No"
my_recitation = "Monday"

if today == "Sunday":
    print("Shvizut Yom Alef")
    if strike == "Y":
        print("Stay home")
    else:
        print("Lecture in intro to CS!")
elif today == "Wednesday":
    print("Another lecture in intro to CS!")
elif today==my_recitation:
    print("Go to recitation!")
elif today=="Monday" or today=="Tuesday" or today=="Friday" or today=="Saturday":
    print("no intro to CS")
else:
    print("Not a day")


# ## Another If-elif-else example

# Two conditional structures:

# In[61]:


n=100
if n > 90 and n%2 == 0:
    print("hi")
if n > 99:
    print("bye")
else:
    print("something")


# Now there is only one conditional structure:

# In[1]:


n=100
if n > 90 and n%2 == 0:
    print("hi")
elif n > 99:
    print("bye")
else:
    print("something")


# ## the function input()

# In[66]:


x = input(" please input an integer: ")
x


# In[67]:


x = input(" please input an integer: ")
int(x)


# ## Introducing Loops!

# ### Simple While Loop

# In[45]:


a = 0
while a < 10:
    print(a)
    a+=1
print("value of a: " + str(a))


# ### Counting the number of zeros in a given integer (solution 1)

# In[68]:


num = int(input("please input an integer: "))
m = num

cnt = 0
while num > 0: # if we change to >= we get an infinite loop
    if num % 10 == 0:
        cnt += 1
    num = num // 10
    
print(m, cnt)


# ### Simple For Loop

# In[50]:


for c in "amir":
    print(c)


# ### Counting the number of zeros in a given integer (solution 2)

# In[52]:


num = input("please input an integer: ")

cnt = 0
for digit in num:
    if digit == "0":
        cnt += 1
print(num, cnt)


# ### Counting the number of zeros in a given integer (solution 3)

# In[54]:


num = input("please input an integer: ")
cnt = str.count(num, "0")
print(num, cnt)


# ## Simple Function Example

# In[58]:


def amir(a):
    return a+1 # as opposed to print which will not return the value 

x = amir(10)
x * 2