# Practice Exercises for Functions
 
# Solve each of the practice exercises below. 

# 1.Write a Python function miles_to_feet that takes a parameter miles and 
# returns the number of feet in miles miles.
def miles_to_feet(miles):
    feet = miles * 5280
    return feet
    
print(miles_to_feet(2.5))
print('=====')

# 2.Write a Python function total_seconds that takes three parameters hours, minutes and seconds and 
# returns the total number of seconds for hours hours, minutes minutes and seconds seconds. 
def total_seconds(hours, minutes, seconds):
    total = hours * 60 * 60 + minutes * 60 + seconds
    return total
    
print(total_seconds(1, 5, 10))
print('=====')

# 3.Write a Python function rectangle_perimeter that takes two parameters width and height 
# corresponding to the lengths of the sides of a rectangle and 
# returns the perimeter of the rectangle in inches. 
def rectangle_perimeter(width, height):
    perimeter = (width + height) * 2
    return perimeter
    
print(rectangle_perimeter(2.3, 2.2))
print('=====')

# 4.Write a Python function rectangle_area that takes two parameters width and height 
# corresponding to the lengths of the sides of a rectangle and 
# returns the area of the rectangle in square inches. 
def rectangle_area(width, height):
    area = width * height
    return area
    
print(rectangle_area(2, 5))
print('=====')

# 5.Write a Python function circle_circumference that takes a single parameter radius 
# corresponding to the radius of a circle in inches and 
# returns the the circumference of a circle with radius radius in inches. 
# Do not use π=3.14, instead use the math module to supply a higher-precision approximation to π. 
import math
def circle_circumference(radius):
    circumference = 2.0 * radius * math.pi
    return circumference
    
print(circle_circumference(4.0))
print('=====')

# 6.Write a Python function circle_area that takes a single parameter radius 
# corresponding to the radius of a circle in inches and 
# returns the the area of a circle with radius radius in square inches. 
# Do not use π=3.14, instead use the math module to supply a higher-precision approximation to π. 
def circle_area(radius):
    area = radius * radius * math.pi
    return area

print(circle_area(4.0))
print('=====')

# 7.Write a Python function future_value that takes three parameters present_value, annual_rate and years and 
# returns the future value of present_value dollars invested at annual_rate percent interest, 
# compounded annually for years years. 
def future_value(present_value, annual_rate, years):
    value = present_value * pow(annual_rate + 1.0, years)
    return value
    
print(future_value(1000000.0, 0.03, 10))
print('=====')

# 8.Write a Python function name_tag that takes as input the parameters first_name and last_name (strings) and 
# returns a string of the form "My name is % %." where the percents are the strings first_name and last_name. 
# Reference the test cases in the provided template for an exact description of 
# the format of the returned string.
def name_tag(first_name, last_name):
    form = "My name is %s %s." % (first_name, last_name)
    return form
    
print(name_tag('Bob', 'Smith'))
print('=====')

# 9.Write a Python function name_and_age that takes as input the parameters name (a string) and age (a number) and 
# returns a string of the form "% is % years old." where the percents are the string forms of name and age. 
# Reference the test cases in the provided template for an exact description of 
# the format of the returned string. 
def name_and_age(name, age):
    form = "%s is %d years old." % (name, age)
    return form
    
print(name_and_age('John', 24))
print('=====')

# 10.Write a Python function point_distance that takes as the parameters x0, y0, x1 and y1, and 
# returns the distance between the points (x0,y0) and (x1,y1). 
def point_distance(x0, y0, x1, y1):
    distance = math.sqrt((x0 - x1)**2 + (y0 - y1)**2)
    return distance
    
print(point_distance(0, 0.5, -2.2, 3.5))
print('=====')

# 11.Challenge: Write a Python function triangle_area that takes the parameters x0, y0, x1,y1, x2, and y2, and 
# returns the area of the triangle with vertices (x0,y0), (x1,y1) and (x2,y2). 
# (Hint: use the function point_distance as a helper function and apply Heron's formula.) 
def triangle_area(x0, y0, x1, y1, x2, y2):
    side1 = point_distance(x0, y0, x1, y1)
    side2 = point_distance(x1, y1, x2, y2)
    side3 = point_distance(x2, y2, x0, y0)
    area = heron_formula(side1, side2, side3)
    return area
    
# 海伦公式
def heron_formula(side1, side2, side3):
    p = (side1 + side2 + side3) / 2.0
    area = math.sqrt(p * (p - side1) * (p - side2) * (p - side3))
    return area
    
print(triangle_area(0, 0.5, -2.2, 3.5, -3, -2.5))
print('=====')

# 12.Challenge: Write a Python function print_digits that takes an integer number in the range [0,100), 
# i.e., at least 0, but less than 100. It prints the message "The tens digit is %, and the ones digit is %.", 
# where the percent signs should be replaced with the appropriate values. 
# (Hint: Use the arithmetic operators for integer division // and remainder % to find the two digits. 
# Note that this function should print the desired message, rather than returning it as a string. 
def print_digits(number):
    tens, ones = number // 10, number % 10
    message = "The tens digit is %d, and the ones digit is %d." % (tens, ones)
    print(message)

print_digits(49)
print('=====')

# 13.Challenge: Powerball is lottery game in which 6 numbers are drawn at random. 
# Players can purchase a lottery ticket with a specific number combination and, 
# if the number on the ticket matches the numbers generated in a random drawing, 
# the player wins a massive jackpot. Write a Python function powerball that takes no arguments and 
# prints the message "Today's numbers are %, %, %, %, and %. The Powerball number is %.". 
# The first five numbers should be random integers in the range [1,60), i.e., at least 1, 
# but less than 60. In reality, these five numbers must all be distinct, but for this problem, 
# we will allow duplicates. The Powerball number is a random integer in the range [1,36), 
# i.e., at least 1 but less than 36. Use the random module and the function random.randrange to 
# generate the appropriate random numbers.Note that this function should print the desired message, 
# rather than returning it as a string. 
import random
def powerball():
    ball1, ball2, ball3, ball4, ball5 = random.sample(range(1,60), 5)
    ball6 = random.choice(range(1, 36))
    message = "Today's numbers are %d, %d, %d, %d, and %d. The Powerball number is %d." % (ball1, ball2, ball3, ball4, ball5, ball6)
    print(message)

powerball()
powerball()
print('=====')