Notes, summaries, assignments, exams, and problems for Computers

1. Why Study Programming Language Concepts?

• Expressiveness: Leverage diverse language features

• Selection: Match language to task (e.g., LISP for AI, PHP for web)

• Learning: Foundations ease uptake of new languages

• Efficiency: Choose constructs (recursion vs. iteration) for performance

• Maintenance: Better code reuse and understanding

2. Programming Domains and Typical Languages

3. Language Categories

• Imperative: Variables + assignment + iteration (C, Java, Python, Perl)

• Functional: Computation

Recursive Binary Tree Traversals

Inorder Traversal:

void inorder(struct node *root)
{
  if(root != NULL)
  {
    inorder(root->left);
    printf("%d\t", root->data);
    inorder(root->right);
  }
}

Preorder Traversal:

void preorder(struct node *root)
{
  if(root != NULL)
  {
    printf("%d\t", root->data);
    preorder(root->left);
    preorder(root->right);
  }
}

Postorder Traversal:

void postorder(struct node *root)
{
  if(root != NULL)
  {
    postorder(root->left);
    postorder(root->right);
    printf("%d\t", root->data);
  }
}

Linked List Operations

Search

void search(struct node *head,int key)
{
  struct node *temp = head;
  while(temp != NULL)
  {
    if(temp->data == key)
      printf("key found");
    temp =

Algorithms

Algorithms involve inputs, instructions, outputs, and a purpose.

Instruction Types

• Instruction
• Decision
• Loop
• Variable
• Function

Python Basics

Comments

Comments explain what code is for, intended for human readers.

Variables

Storing a value in a variable is called assignment. It's best practice not to use generic names.

Calculations (Operators)

• + : Addition
• - : Subtraction
• * : Multiplication
• / : Division
• // : Integer Division (e.g., 6 // 4 = 1)
• % : Remainder / Modulo (e.g., 6 % 4 = 2)
• ** : Exponentiation

mass_in_kg = 15

weight_in_pounds = mass_in_kg * 2.2

print('the weight in pounds is: ', weight_in_pounds)

user_name = input("enter your user name: ")

print('hello', user_name)

Data Types

• int: Integer numbers (e.g., -1, 0, 2, 1000)
• float: Floating-point (real)

Lecture 1: Moore's Law

Moore's Law: The number of transistors on microchips doubles every two years.

Lecture 2: Logic Gates

AND, OR, and NOT gates are universal.

Logic word problem steps:

Example: In a bank, there were four employees: the bank manager, assistant manager, teller, and the security guard. The bank has a single vault for the storage of their money. This vault was designed so that it needs four signals to open it. These four signals are from the bank manager, assistant manager, teller, and the security guard. For the vault to open, it needs the following conditions:

1. No single employee can open the vault.
2. It can be opened with three employees as long as one of them is the manager.
3. It can be opened by the manager together with the assistant

A stack is a fundamental data structure in computer science that follows the Last In, First Out (LIFO) principle. This means that the last element added to the stack is the first one to be removed. You can think of it like a stack of plates: you can only add or remove the top plate.

### Key Concepts of a Stack:

1. Basic Operations:
   - Push: This operation adds an element to the top of the stack.
   - Pop: This operation removes the element from the top of the stack and returns it.
   - Peek (or Top): This operation returns the top element of the stack without removing it.
   - IsEmpty: This operation checks whether the stack is empty.

2. Implementation:
   Stacks can be implemented using arrays or linked lists. Here are the details for... Continue reading "Mastering Stacks, Deques, Trees, and Graph Data Structures" »

Microprocessor vs. Microcontroller

ii) Differentiate Between a Microprocessor and a Micro-Controller

Microprocessor

Definition:

A microprocessor is a central processing unit (CPU) on a single integrated circuit (IC) chip that performs the processing functions of a computer.

Functionality:

• It only includes the CPU core and lacks other components like memory, I/O ports, timers, and other peripherals.
• Requires external components like memory (RAM, ROM), input/output devices, timers, and other peripherals to function as a complete system.

Usage:

• Primarily used in systems requiring high computational power and flexibility, such as desktop computers, laptops, servers, and high-end embedded systems.
• Suited for applications where customization of peripherals

Key .NET Concepts Defined

Managed Code Explained

Managed code is the code executed by the .NET runtime (CLR), which provides memory management, security, and exception handling.

.NET Framework Class Library (FCL)

FCL is a collection of reusable classes, interfaces, and value types that provide core functionalities like file handling, data access, and networking in .NET applications.

Boxing in VB.NET

Boxing is the process of converting a value type (e.g., Integer) into an object type (Object), allowing it to be stored in the heap.

Option Explicit Statement

In VB.NET, Option Explicit forces variable declarations before use, preventing errors due to undeclared variables.

Progress Bar Control Use

A Progress Bar control visually represents the progress of... Continue reading "Essential .NET Concepts: CLR, FCL, MSII" »

Essential Linux Commands

File and Directory Management

• mkdir: Create a new directory.
• ls: List contents of a directory.
• rm: Remove files or directories (-r for recursive).
• cp: Copy files or directories.
• mv: Move or rename files or directories.
• cat: Display file contents or create files.
• less: View file contents one page at a time.
• head: Display the first 10 lines of a file.
• tail: Display the last 10 lines of a file.

System Information

• uname: Show system information (kernel, version, etc.).
• top: Display running processes and resource usage.
• df: Show disk space usage.
• df -h: Show disk usage in human-readable format.
• free: Display memory usage (RAM and swap).

File Creation and Editing

• touch: Create an empty file or update its timestamp.
• echo: Write text to a file

1. TCP Congestion Control

Slow Start: TCP initializes congestion window (cwnd) to a small size and doubles it every Round Trip Time (RTT) until a loss occurs (exponential growth) or the slow start threshold is reached.

Congestion Avoidance: After reaching the threshold, cwnd is incremented by one segment for each RTT, growing linearly to avoid congestion.

Fast Recovery: When triple duplicate ACKs are detected, TCP halves the cwnd and reduces the slow start threshold to half of the cwnd size before the loss, then transitions to congestion avoidance.

2. TCP RTT and Timeout

Estimating RTT: Uses Smoothed Round Trip Time (SRTT) which is a weighted average of previous RTT measurements.

Timeout Calculation: Often calculated as Timeout=SRTT+4×RTT

Windows Popularity and Vista Features

Unit 13

Interviewer: There is no doubt that Windows has revolutionized the way we use computers today. Bill, can you explain just why it’s so popular?

Bill: Well, very simply, people find Windows very easy to use because everything is presented in graphic images. It’s also compatible with thousands of programs.

Interviewer: The big news at the moment is, of course, the launch of Windows Vista – the successor to Windows XP. I understand that there are several versions of Vista available. Could you give us some advice on which one to get?

Bill: Yes, you’re right – there are four main editions: Home Basic, Home Premium, Business and Ultimate.

Windows Vista Editions:

• Home Basic: Designed for users with basic