- 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
percenTaxed = 10

PROCEDURE applyTax(cost, percentTaxed)
{
    temp ← 100 + percentTaxed
    temp← temp/ 100
    cost ← cost *temp
    RETURN(cost)
}

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 subtract(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(subtract(123456789, 123456));

123333333

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);

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

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

# Codes here


class car:
    def __init__(model, vehicleName, price ): 
        model.vehicleName = vehicleName;
        model.price = price;
    
    def getName(model): # method to create get name
        return model.vehicleName;
    
    def getAge(model): # method to create get age
        return model.price;
    
    def setName(model, vehicleName): # method to create set name
        model.model = vehicleName;
        
    def setAge(model, price): # method to create set age
        model.model = price;
        
    def yearOlder(model): # method to increment age by 1
        model.price += 1;
        
    def __str__(model): # method that returns a string when the object is printed
        return (f"My car is {model.vehicleName} and the price is {model.price}.")

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

My car is Honda Civic and the price is 13000.

Homework:

UPDATED 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].

aar1 = [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(arr1):
    arr = [];
    for i in arr1:
        if i in arr:
            pass;   
        else:
            arr.append(i);
    return arr;
print(distinct(aar1))

[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

# Defining Classes
class person:
    def __init__(self, email, name, grade ): # constructor
        self.email = email;
        self.name = name;
        self.grade = grade;
    
    def getName(self): # method to create get name
        return self.email;
    
    def getAge(self): # method to create get age
        return self.name;

    def getAge(self): # method to create get age
        return self.grade;
    
    def setName(self, email): # method to create set name
        self.email = email;
        
    def setAge(self, name): # method to create set age
        self.name = name;
        
    def setName(self, grade): # method to create set name
        self.grade = grade;
    
    def yearOlder(self): # method to increment age by 1
        self.grade += 1;
        
    def __str__(self): # method that returns a string when the object is printed
        return (f"My name is {self.name}. My email is {self.grade}. My grade is {self.email}")

Person1 = person("blablabla@gmail.com", "Jason G", 96);

print(Person1);

My name is Jason G. My email is 96. My grade is blablabla@gmail.com