- 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
cost = 50

def applyTax(cost, percentTaxed):
    temp = 100 + percentTaxed
    temp = temp/100
    cost = cost * temp
    return cost

price = applyTax(cost,10)

print(price)

55.00000000000001

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

def subtract(num1, num2):
    solution = num1 - num2
    return(solution)

subtract(2, 1)

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:
    def __init__(self, name, year, price, ):
        self.name = name
        self.year = year
        self.price = price
    
    def getName(self):
        return self.name

    def getYear(self):
        return self.year

    def getPrice(self):
        return self.price

    def __str__(self):
        return (f"Name: {self.name} Year: {self.year} Price {self.price}")


car1 = car("Honda Civic", 2018, 13000)
print(car1)

car2 = car("Honda Civic", 2018, 13000)
print(car2)

car3 = car("Honda Civic", 2018, 13000)
print(car3)

Name: Honda Civic Year: 2018 Price 13000
Name: Honda Civic Year: 2018 Price 13000
Name: Honda Civic Year: 2018 Price 13000

Homework:

HW 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 get_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]
distinct_values = get_distinct_values(arr1)

print(distinct_values)

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

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, name, email, grade, ):
        self.name = name
        self.email = email
        self.grade = grade
    
    def getName(self):
        return self.name
    
    def getEmail(self):
        return self.email
    
    def getGrade(self):
        return self.grade
    
    def __str__(self):
        return (f"My name is {self.name}. My email is {self.email}. My grade is {self.grade}.")
    
me = student("Ninaad", "ninaadk54710@stu.powayusd.com", 93)
print(me)

My name is Ninaad. My email is ninaadk54710@stu.powayusd.com. My grade is 93.