IT101 IT Fundamentals - Lectures 7 & 8

IT101 IT Fundamentals

• Course instructors: Dr. Islam Taj-Eddin, Dr. Ali Hussein Ahmed, Dr. Tarik Mohamed Abdel-Kader Ibrahim, Dr. Ebram Kamal William Aziz
• Department: IT Department, Faculty of Computers and Information
• University: Assiut University
• Academic year: 2024-2025

Course Enrollment

• Learning management system (LMS): Thinqi LMS
• Course code: IT101-1
• Group: 1 - 2024/2025
• Course name: IT Fundamentals
• Enroll using the provided QR code at the given URL: https://aun.edu.eg/thinqi

Lecture 7&8

• Topic: Programming
• Number of the lecture: 7 & 8

What is C?

• Programming language created by Dennis Ritchie at Bell Laboratories in 1972
• A versatile, popular language, despite its age
• Closely associated with the UNIX operating system, as it was designed for its development

Why Learn C?

• One of the most popular programming languages globally
• Learning C lays a strong foundation for other languages (Java, Python, C++, C#) due to similar syntax
• Compiled language, making it significantly faster compared to interpreted languages (like Java and Python)

Difference between C and C++

• C++ is an extension of C
• Both languages share a similar syntax
• C++ supports classes and objects; C does not

C Programming Language

• Structured, relatively low-level, and portable programming language
• It influences many other programming languages
• Forces understanding of fundamental programming concepts.
• Characterized by its conciseness

C, Continued

• Not an object-oriented language (C++ is)
• Can be useful as a non-object-oriented language
• Learning curve is manageable.
• ANSI standard defines C for portability

C Install IDE

• Integrated Development Environment (IDE) is used to edit and compile code
• Popular IDEs include Code::Blocks, Eclipse, and Visual Studio. These are all freely available
• Web-based IDEs are also available but may have limitations in functionality
• Code::Blocks is used in tutorials as a strong and effective choice
• Download the mingw-setup.exe file from http://www.codeblocks.org/
• Online compilers are available at https://www.programiz.com/c-programming/online-compiler/

C Data Types

• Topic: C data types

What do program instructions look like?

• Simple programs generally contain at least:
• Variable declaration
• Variable initialization
• Main body

Variables in Programming

• Representing storage units in a program
• Used for storing and retrieving data throughout program execution
• Variable type dictates the data it can hold
• Variables are declared before assignment.
• Variables can change values; constants remain constant

Naming Variables

• Variables are assigned names when declared
• Good programming practices: choose names that reflect the variables' roles in the program (e.g., customer_name, ss_number) Avoid vague or confusing abbreviations
• Avoid overly long names unless readability improves.
• Naming restrictions: variable names must begin with a letter and can contain letters, digits, and underscores. C is case-sensitive; use 31 or fewer characters for portability

Variable Declaration

• All variables must be declared in a C program before the first executable statement
• Examples of declarations for integer and float types can be found in the slides

C Variable Names

• Variables in C consist of letters, digits and underscores, and cannot start with a digit
• Variable names are case-sensitive
• ANSI standards limit variable names to 31 characters or less

Variable assignment

• After declaring a variable, it should be given a value through assignment using the equals operator (=)

Basic C variable types

• There are four basic types in C:
• char: A single byte holding a character from the local character set.
• int: Represents an integer of a size that varies based on the machine architecture.
• float: Single-precision floating-point number
• double: Double-precision floating-point number

char variable type

• Represents a single byte (8 bits) of storage
• Can be signed or unsigned
• Internals are numerical values associated with characters (ASCII) via a character set

int variable type

• Represents a signed integer, typically using 4 bytes (32 bits)

Char vs. Int

• Both can perfectly represent the same number (e.g., 4)
• Ints store more memory but can also hold numbers larger than 255 -Chars typically represent a single byte and have a limited range

Char, Continued

• Avoid using char for larger numbers to prevent data loss situations

Float and Double Variable Types

• These represent real numbers, typically using 32 and 64 bits respectively

Additional variable types

• Other variable types can be created using modifiers (e.g., short, long, signed, unsigned)
• Exact sizes depend on the machine, and are not essential for basic programming for this course.

Declaring Variables

• All variables should be declared before executable instructions
• A declaration includes the variable's type followed by its name (e.g., int age;, float annual_salary;)

Assigning Values to Variables

• Variable assignments can be done directly in the declaration or after declarations
• Use the = assignment operator (e.g., output = input + 1;)

Assignment, Continued

• Be mindful of variable types when assigning values.
• Ensure that assignment won't cause an overflow

Type conversions in expressions

• Implicit type conversion occurs when mixing data types in an expression
• The lower type is promoted to the higher type.
• C allows mixing of data types in an expression, converting smaller types into larger type before the expression evaluates, for instance converting short to int before computing an expression with int values.

Order of Data Types

• Data types are ordered in terms of their size or range.
• Larger types generally precede smaller types in the ordering

Printf() examples

• printf("string"); Prints a string to the console.
• printf("%d", variable); Prints the integer value of the variable to the console.

Reading keyboard input

• Scanf function reads input from user input from the keyboard.
• It is like printf but it is for reading user input

Scanf function

• Syntax: scanf(format, &variable)
• Format specifiers are similar to printf.

Another technique for passing data from the keyboard

• Passing data to a C program using argc and argv

Passing data, cont

• Tokens are stored as separate elements of the argv array
• argc stores the count of tokens, useful for looping

Argv/argv example

• Example illustrating argc and argv usage

Argv/argv cont

• Processing command-line arguments (tokens) is necessary to handle command-line arguments for advanced scenarios

Converting String to integer

• atoi function converts a string to an integer

Reading single characters

• getchar/putchar reads/writes characters to/from the console.
• getchar waits until input is available from stdin—keyboard—or returns immediately if it is EOF.

While loops

• Repeating statements based on a condition.
• Syntax: while (condition) { ... } condition tested at the beginning of the loop
• Looping continues as long as the expression is true. Example:

While example

• Example demonstrating a while loop, inputting from user
• Includes declarations.

If example

• Includes control flow using if statement
• Includes checks for arguments before entering the loop for validity. Also handles the case where a program only receives its name as an argument.

Getchar/putchar example

• This includes a do-while loop, reading characters one by one

More control statements

• Additional control flow concepts, beyond if, while, and loops

For loops

• Syntax for for loops, equivalent to while loops
• Initialization, condition, and increment parts are separated by semicolons
• Looping structure

For loops, cont

• Specific components of the for loop syntax, including initialization and increment clauses, and the termination condition
• Notes about for loop increments

Switch statements

• A multi-way branching structure switch( expression ) { case value1: // statements break; case value2: // statements break; default: // statements }
• Using break is crucial to prevent fall-through from one case to another

Switch, cont

• Case values must be constants
• break statements in switch are important
• Cleaner alternative for if-else

Switch flow-chart

• Flow chart representation of switch statements

do/while Repetition Structure

• Condition tested at the end of the loop, ensuring the loop runs at least once.
• Structure: do{ ... } while(condition);

Do-while example

• Sample usage of do-while loop

Summary of Control Statements

• Additional control flow statements in C (for, switch, do-while)
• How they increase the versatility and efficiency of programming code

This quiz focuses on Lectures 7 and 8 of the IT101 IT Fundamentals course, covering the C programming language. Delve into the history, significance, and reasons to learn C, a vital foundation for many modern programming languages. Perfect for students aiming to solidify their programming skills.