Procedural vs object-oriented approach in Python - Visual Side-by-Side Comparison

Concept Flow - Procedural vs object-oriented approach

Start

↓

Choose Approach

↓

Procedural

→Write functions

↓

Object-Oriented

→Define class

This flow shows two ways to organize code: procedural uses functions step-by-step, object-oriented uses classes and objects with methods.

Execution Sample

Python

def add_proc(x, y):
    return x + y

class Adder:
    def add(self, x, y):
        return x + y

result_proc = add_proc(2, 3)
adder = Adder()
result_obj = adder.add(2, 3)
print(result_proc)
print(result_obj)

This code shows adding two numbers using a procedural function and an object-oriented class method.

Execution Table

Step	Action	Evaluation	Result
1	Define function add_proc	Store function in memory	Function ready to use
2	Define class Adder with method add	Store class and method	Class ready to create objects
3	Call add_proc(2, 3)	Add 2 + 3	5
4	Create object adder = Adder()	Allocate object	Object adder created
5	Call adder.add(2, 3)	Call method add with 2,3	5
6	Print results	Output values	5 and 5 printed

💡 All steps executed, program ends after printing results

Variable Tracker

Variable	Start	After Step 3	After Step 4	After Step 5	Final
add_proc	undefined	function stored	function stored	function stored	function stored
Adder	undefined	class stored	class stored	class stored	class stored
adder	undefined	undefined	object created	object created	object created
result_proc	undefined	5	5	5	5
result_obj	undefined	undefined	undefined	5	5

Key Moments - 3 Insights

Why do we need to create an object to use the add method in the object-oriented approach?

Because the add method is inside the class and works on objects, so we must create an object (see execution_table step 4 and 5) to call the method.

Can we call the procedural function without creating anything?

Yes, the procedural function is standalone and can be called directly (see execution_table step 3).

Are the results from both approaches the same?

Yes, both return 5 when adding 2 and 3 (see execution_table steps 3 and 5).

Visual Quiz - 3 Questions

Look at the execution_table, what is the result of calling add_proc(2, 3)?

A 2

B 3

C 5

D Error

💡 Hint

Check execution_table row 3 under Result column

At which step is the object 'adder' created?

A Step 4

B Step 3

C Step 5

D Step 2

💡 Hint

Look at execution_table row 4 Action column

If we remove the class and only keep the procedural function, what changes in variable_tracker?

A 'result_obj' will be 5

B 'adder' variable will be undefined throughout

C 'add_proc' will be undefined

D 'Adder' will be an object

💡 Hint

See variable_tracker row for 'adder' which is created only after Step 4

Concept Snapshot

Procedural approach:
- Write functions
- Call functions directly
- Simple and linear

Object-oriented approach:
- Define classes
- Create objects
- Call methods on objects

Both can produce same results but organize code differently.

Full Transcript

This lesson compares procedural and object-oriented programming. Procedural uses functions you call directly. Object-oriented uses classes to create objects, then calls methods on those objects. The example adds two numbers both ways. The execution table shows defining functions and classes, calling them, and printing results. Variables track function, class, and object states. Key moments clarify why objects are needed for methods and that procedural functions are standalone. The quiz checks understanding of steps and variable states. The snapshot summarizes the main differences simply.