- 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?

PROCEDURE applyTax(cost, percentTaxed)
{
    temp ← 100 + percentTaxed
    temp← temp/ 100
    cost ← cost *temp
    RETURN(cost)
}
price ← applyTax(price, 10)
This applys the 10% tax to the price determined after the discount.

What Are Functions?

Collections of code
Divides large program into smaller chunks
Better readability
Less repetitive code
More efficient code
Good organization

What Are The Components of a Function?

The function declaration
The parameters (input). This is also referred to as an argument when a value is being passed to the actual function.
The functionality
The return value (output)
Calling the 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
def minus(parameter1, parameter2):
    solution = parameter1 - parameter2;
    return solution;
print(minus(10,56));
def multiply(parameter1, parameter2):
    solution = parameter1 * parameter2;
    return solution;
print(multiply(10,600));
def divide(parameter1, parameter2):
    solution = parameter1 / parameter2;
    return solution;
print(divide(14,600));

-46
6000
0.023333333333333334

What is a Class?

A class is an outline for a set of nested functions and variables.
There are instance variables
Functions

Constructor method (Required)
To String method
Getter method
Setter method

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);

Popcorn Hack 3:

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

2. Create instances of the following cars

Name: Honda Civic , Model Year: 2018 , Price: $13,000
Name: Toyota Prius, Model Year: 2023 , Price: $28,000
Name: Chevrolet Impala, Model Year: 2020 , Price: $22,000

class Car: # Changed class name to start with an uppercase letter (convention)
    def __init__(self, model, vehicle, price): # constructor
        self.model = model;
        self.vehicle = vehicle;
        self.price = price;
        
    def getModel(self): # method to create get name
        return self.model;
    
    def getVehicle(self): # method to create get name
        return self.vehicle;
    
    def getPrice(self): # method to create get name
        return self.price;
    
    def setModel(self, model): # method to create set name
        self.model = model;
        
    def setVehicle(self, vehicle): # method to create set name
        self.vehicle = vehicle; # Fixed the typo here
        
    def setPrice(self, Price): # method to create set name
        self.price = Price;
        
    def __str__(self): # method that returns a string when the object is printed
        return (f"The car model is {self.model} and it is a {self.vehicle} and it costs {self.price} dollars.")
    
Car1 = Car("a Honda Civic", 2018, 13000); # Changed commas to periods

Car2 = Car("a Toyota Prius", 2023, 28000); # Changed commas to periods

Car3 = Car("a Chevrolet Impala", 2020, 22000); # Changed commas to periods

Car4 = Car("a ")
print(Car1);
print(Car2);
print(Car3);

The car model is a Honda Civic and it is a 2018 and it costs 13000 dollars.
The car model is a Toyota Prius and it is a 2023 and it costs 28000 dollars.
The car model is a Chevrolet Impala and it is a 2020 and it costs 22000 dollars.

assignment 1: Create a function that takes in an array as the parameter and returns the array of distinct values. DON’T USE SETS. TEST ARRAY: arr1 = [2,1,3,2,0,2,0,0,4,2,0,0,0,2,0,0,1,2,3,0,7,4,5,2,1,2,3,4,6]

def distinct_values(arr):
    distinct_arr = []
    for item in arr:
        if item not in distinct_arr:
            distinct_arr.append(item)
    return distinct_arr
arr1 = [2,1,3,2,0,2,0,0,4,2,0,0,0,2,0,0,1,2,3,0,7,4,5,2,1,2,3,4,6]
result = distinct_values(arr1)
print(result)

[2, 1, 3, 0, 4, 7, 5, 6]

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):
    #code here

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

Assignment 2:

Create a student class that...

Has a constructor that takes three parameters as attributes
- email
- name
- grade
Three getter methods to access the name, email, and grade
Three setter methods to modify the name, email, and grade
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}
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

    def get_name(self):
        return self.name
    
    def get_email(self):
        return self.email
    
    def get_grade(self):
        return self.grade

    def set_name(self, new_name):
        self.name = new_name
    
    def set_email(self, new_email):
        self.email = new_email
    
    def set_grade(self, new_grade):
        self.grade = new_grade

    def __str__(self):
        return f"My name is {self.name}. My email is {self.email}. My grade is {self.grade}"

# Create an instance of the class corresponding to you
my_student = Student("yourmom@gmail.com", "Lincoln", "A+")

# Accessing attributes and printing the student information
print("Name:", my_student.get_name())
print("Email:", my_student.get_email())
print("Grade:", my_student.get_grade())

# Modifying attributes
my_student.set_name("Lincoln Crowell")
my_student.set_email("LBozo@hotmail.com")
my_student.set_grade("A")

# Printing updated information
print(my_student)

Name: Lincoln
Email: yourmom@gmail.com
Grade: A+
My name is Lincoln Crowell. My email is LBozo@hotmail.com. My grade is A