Takeaways

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- CB 3.12,3.13 Developing Procedures

What is a procedure?

A procedure is a named group of code that has paramaters and return values. Procedures are known as methods or functions depending on the language.

A procedure executes the statements within it on the parameters to provide a return value.

What are parameters?

Paramaters are input values of a procedure that are specified by arguments.Arguments specify the values of the parameters when a procedure is called.

By creating theses algorithms the readibility of code increases and the complexity decreases. This is becasue a function’s name can tell the reader what action it will perform, and by calling it, the code becomes more clean and easy to understand.

What is a return value?

A return value is the value that is returned when a function or a method is called.

That return value can be assigned or printed

Procedures are used to create algorthims that can perform certain actions or return values. When a procedure returns a value, theis information must be stored in a variable for later use. However some procedures like the MOVE_FORWARD() perform an action, and don’t return a value. The image above provides an example of where procedures that don’t output a value would be used.

A 60$ item recieves a 20% discount and taxed at 8%.
PROCEDURE applyDiscount(cost, percentDiscounted)
{
    temp  100 - percentDiscounted
    temp temp/ 100
    cost  cost *temp
    RETURN(cost)
}

price  applyDiscount(60, 20)
This is how we get the final price with the discount by calling the procedure and assigning it to the price variable.


PROCEDURE applyTax(cost, percentTaxed)
{
    temp  100 + percentTaxed
    temp temp/ 100
    cost  cost *temp
    RETURN(cost)
}
price  applyTax(price, 8)
This applys the 8% tax to the price determined after the discount.

Popcorn Hack 1

Given the applyTax procedure above: How would you call the procedure to get it to find the price using cost = 50, and percentTaxed = 10, and what value will it return?

#code here

price <- applyTax(50, 10);
# value returned 55

What Are Functions?

What Are The Components of a Function?

# Defining Functions
#
# def function_name(parameter1, parameter2, etc..):
#     code here...
#
#     return return_value;

# return the value of parameter1 plus parameter2;
def add(parameter1, parameter2): # creates a function that takes in two parameters
    solution = parameter1 + parameter2; # sets solution to the sum of parameter1 and parameter2
    return solution; # return solution
    
print(add(5, 5)); # prints the return value of add(5,5)

Popcorn Hack 2:

1. Make a function that returns the difference of two numbers

# Code here

num1 = int(input("enter a number"))
num2 = int(input("enter another tomorrow"))

def diffNum(num1, num2):
    solution = abs(num1 - num2)
    print(solution)

diffNum(num1, num2)
5

What is a Class?

How Does a Class Work?

# Defining Classes
class person:
    def __init__(self, name, age, ): # constructor
        self.name = name;
        self.age = age;
    
    def getName(self): # method to create get name
        return self.name;
    
    def getAge(self): # method to create get age
        return self.age;
    
    def setName(self, name): # method to create set name
        self.name = name;
        
    def setAge(self, age): # method to create set age
        self.age = age;
        
    def yearOlder(self): # method to increment age by 1
        self.age += 1;
        
    def __str__(self): # method that returns a string when the object is printed
        return (f"My name is {self.name} and I am {self.age} years old.")

Person1 = person("John Doe", 15);
print(Person1)


print(Person1);
My name is John Doe and I am 15 years old.
My name is John Doe and I am 15 years old.

Popcorn Hack 3:

1. Create a Car class which has the attributes model, vehicle name, and price

2. Create instances of the following cars

# Defining Classes
class car:
    def __init__(self, name, age, cost): # constructor
        self.name = name
        self.age = age
        self.cost = cost
    
    def getName(self): # method to create get name
        return self.name

    def getCost():
        return self.cost
    
    def getAge(self): # method to create get age
        return self.age
    
    def setName(self, name): # method to create set name
        self.name = name
    
    def setAge(self, age): # method to create set age
        self.age = age
        
    def yearOlder(self): # method to increment age by 1
        self.age += 1
        
    def __str__(self): # method that returns a string when the object is printed
        return (f"My car is a {self.name} from {self.age} and it costed ${self.cost}.")

car1 = car("Honda Civic", 2018, 13000)
car2 = car("Toyota Prius", 2023, 28000)
car3 = car("Chevrolet Impala", 2020, 22000)
print(car1)
print(car2)
print(car3)
My car is a Honda Civic from 2018 and it costed $13000.
My car is a Toyota Prius from 2023 and it costed $28000.
My car is a Chevrolet Impala from 2020 and it costed $22000.

Homework:

Assignment 1: How do you use functions?

Create a turtle python function that...

  1. Takes a single parameter as the number of sides
  2. Outputs a shape corresponding to the number of sides
  3. Call the function with the argument being a variable with the user input

Hint:

import turtle

pen = turtle.Turtle(); # pen is the instance of Turtle which has methods that do certain actions

# Necessary methods:
# .forward(50) - moves the pen forward 50 units
# .right(angle) - turns the pen angle degrees right   
# OR
# .left(angle) - turns the pen angle degrees left

def shape(sides):
    angle = ((sides-2)*180)
    print(angle)
    angle /= sides
    for i in range(sides):
        pen.forward(40)
        pen.right(angle)

numsides = int(input('How many sides do yoUUUU wnat in YOUUUURRRR shape?!?!!?!: '))
shape(numsides)

Assignment 2:

Create a student class that...

  1. Has a constructor that takes three parameters as attributes
    • email
    • name
    • grade
  2. Three getter methods to access the name, email, and grade
  3. Three setter methods to modify the name, email, and grade
  4. A to string method that returns the three instance variables in this format - "My name is {name}. My email is {email}. My grade is {grade}
  5. Create an instance of the class that corresponds with you
class Student:
    def __init__(self, email, name, grade):
        self.email = email
        self.name = name
        self.grade = grade

    # Getter methods
    def get_name(self):
        return self.name

    def get_email(self):
        return self.email

    def get_grade(self):
        return self.grade

    # Setter methods
    def set_name(self, name):
        self.name = name

    def set_email(self, email):
        self.email = email

    def set_grade(self, grade):
        self.grade = grade

    def to_string(self):
        return f"My name is {self.name}. My email is {self.email}. My grade is an {self.grade} cuz I'm the goat"

# Create an instance of the Student class
dudeman = Student("dudeamabobby@gmail.com", "Dude Bobby", "A")

# Print the student's information
print(dudeman)