Unit 3 – Programming Fundamentals (XI Computer Science – FBISE)

Описание: Programming Language

A programming language is a formal language used to write instructions that a computer can understand and execute.

Examples:

Python

Java

C++

JavaScript

Programming languages act as a bridge between humans and computers.

3.1 Computer Program

A computer program is a complete set of instructions stored in memory that directs a computer to perform operations on data.

Types of Programs:

System programs (Operating systems)

Application programs (Word processors, browsers)

Utility programs (Antivirus, backup tools)

Compiler

A compiler is a translator program that converts a high-level language program into machine language at once. I

Features of Compiler:

Translates whole program at once

Generates object code

Faster execution after compilation

Errors are reported after full translation

Example: C and C++ use compilers.

Interpreter

An interpreter translates and executes a program line by line.

Features of Interpreter:

Line-by-line translation

Slower execution

Easier debugging

Used in interactive environments

Example: Python uses an interpreter.

Assembler

An assembler converts assembly language (low-level language) into machine code.

Characteristics:

One-to-one translation

Machine dependent

Faster execution

Hardware specific

High-Level Languages

High-level languages are user-friendly and closer to human language. They hide hardware details and are easy to learn, write, and maintain.

Examples:

Python

Java

C#

Pascal

Advantages:

Easy to understand

Portable

Less time-consuming

Rich libraries

Low-Level Languages

Low-level languages are closer to machine language and hardware.

Types:

Machine language (0s and 1s)

Assembly language

Advantages:

Fast execution

Efficient memory usage

Direct hardware control

Disadvantages:

Difficult to learn

Machine dependent

Error-prone

Interactive Programs

Interactive programs interact with users during execution. They take input from the user and produce output immediately.

Examples:

Calculator

ATM system

Online forms

Characteristics:

User-driven

Real-time processing

Immediate feedback

Batch Programs

Batch programs process a large volume of data without user interaction. Input is collected first, then processed as a batch.

Examples:

Payroll systems

Examination result processing

Bank statement generation

3.2 Python: An Overview

Python is a high-level, interpreted, general-purpose programming language developed by Guido van Rossum in 1991. It emphasizes simplicity and readability.

Features of Python:

Easy syntax

Interpreted language

Object-oriented

Platform independent

Large standard library

Free and open-source

Python is widely used in:

Education

Web development

Data science

Artificial intelligence

Automation

3.3 Python IDE and Its Components

An IDE (Integrated Development Environment) is software that provides tools to write, edit, run, and debug programs.

Common Python IDEs:

IDLE

PyCharm

VS Code

Jupyter Notebook

Components of Python IDE:

Editor – Used to write Python code

Interpreter – Executes Python programs

Debugger – Helps find and fix errors

Console/Output Window – Displays output

File Manager – Manages program files

3.4 Turtle Library: An Introduction

The turtle library in Python is a graphical module used to draw shapes and patterns. It is especially useful for beginners to learn programming concepts visually.

Key Concepts:

Turtle (cursor)

Screen

Movement commands

Common Turtle Commands:

forward()

backward()

left()

right()

penup()

pendown()

Turtle graphics help in understanding:

Loops

Functions

Coordinates

Logic building

3.5 Libraries in Python

A library is a collection of pre-written code that can be reused to perform common tasks.

Examples of Python Libraries:

math

random

datetime

turtle

Benefits:

Saves time

Reduces errors

Improves productivity

Code reusability

Datetime Library & strftime()

The datetime library is used to work with dates and times in Python.

strftime() Function:

It formats date and time into readable strings.

Common Arguments:

%Y → Year

%m → Month

%d → Day

%H → Hour

%M → Minute

%S → Second

Example Demonstration:
from datetime import datetime

now = datetime.now()
print(now.strftime("%Y-%m-%d %H:%M:%S"))


This displays the current date and time in a formatted form.

Conclusion

Unit 3 provides the foundation of programming by introducing programs, languages, translators, Python basics, IDEs, libraries, and graphical tools like turtle. Mastery of these concepts prepares students for advanced programming and real-world problem-solving.