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

This revision sheet covers essential concepts for Advanced Web Designing and Advanced JavaScript exams, designed for effective last-minute study.

🧠 Advanced Web Design & JavaScript Revision

1. Fill in the Blanks (10 Marks)

1. HTML stands for HyperText Markup Language.
2. CSS is used for styling web pages.
3. The <div> tag is a block-level element.
4. The <span> tag is an inline element.
5. External CSS files use the .css extension.
6. JavaScript is a client-side scripting language.
7. The <script> tag is used to embed JavaScript code in HTML.
8. document.write() is used to print content on a web page.
9. var, let, and const are used to declare variables in JavaScript.
10. The href attribute is used in the <a> tag to link to another page.

2. True or False

Palindrome and Digit Sum Calculation

#include <iostream>
using namespace std;
int main() {
    int n, r, rev = 0, sum = 0, t;
    cin >> n; t = n;
    while (n) {
        r = n % 10;
        rev = rev * 10 + r;
        sum += r;
        n /= 10;
    }
    cout << (t == rev ? "Palindrome" : "Not");
    cout << "\nSum=" << sum;
}

Matrix Addition in C++

#include <iostream>
using namespace std;
int main() {
    int a[10][10], b[10][10], c[10][10], r, col;
    cin >> r >> col;
    for (int i = 0; i < r; i++)
        for (int j = 0; j < col; j++) cin >> a[i][j];
    for (int i = 0; i < r; i++)
        for (int j = 0; j < col; j++) cin >> b[i][j];
    for (int i = 0; i < r; i+

Understanding Servlet Architecture for Java Web Applications

Servlet architecture is a core component of Java EE (Enterprise Edition) used for building dynamic web applications. A Servlet is a Java class that runs on a web server and acts as a middle layer between client requests (typically from a browser) and server responses (usually from a database or application logic).

What is a Servlet?

A Servlet is a Java class used to handle HTTP requests and responses in web applications. It runs on a server, receives requests from a client (usually a browser), processes them (e.g., reads form data, interacts with a database), and sends back a dynamic response (like HTML or JSON).

Key Components of Servlet Architecture

• Client (Browser): Sends an HTTP request

Operators

• Arithmetic: +, -, *, /, %
• Relation: ==, !=, >, <, >=, <=
• Logic: &&, ||, !
• Assignment: =, +=, -=, *=, /=, ?=
• Increment: ++, --
• Order of operations: (), *, /, %, +, -, <>, ==, !=

ASCII Conversions

• Lowercase to uppercase: 'x' - 32
• Uppercase to lowercase: 'x' + 32

Data Types

Constants

#define TAX 0.13
const int Max = 100;

Control Structures

Statements: if, else if, else

Switches

switch(x) {
    case 1: printf("One"); break;
    case 2: printf("Two"); break;
    default: printf("Other");
}

Loops: while, do while, for

For Loop Example

#include <stdio.

Single Inheritance in Java

Single inheritance involves one class inheriting properties and methods from exactly one parent class. Below is a demonstration using the Animal and Dog classes.

class Animal {
    Animal() {
        System.out.println("Animal constructor called");
    }
    void eat() {
        System.out.println("I can eat");
    }
}

class Dog extends Animal {
    Dog() {
        System.out.println("Dog constructor called");
    }
    void bark() {
        System.out.println("I can bark");
    }
}

public class Main {
    public static void main(String[] args) {
        Dog myDog = new Dog();
        myDog.eat();
        myDog.bark();
    }
}

Implementing Multiple Inheritance using Interfaces

Java does not support multiple inheritance... Continue reading "Java OOP Concepts: Inheritance and Polymorphism Examples" »

C# Design Patterns: Essential Reference

Creational Design Patterns

Structural Design Patterns

Store Fibonacci Series in an Array

Exam Source: 2024 Q6(b)

Note: fib[0]=0, fib[1]=1, fib[i] = fib[i-1] + fib[i-2] for i >= 2.

#include <stdio.h>

int main() {
    int n, i;
    printf("How many terms? ");
    scanf("%d", &n);
    int fib[n];
    fib[0] = 0;
    if (n > 1) fib[1] = 1;
    for (i = 2; i < n; i++)
        fib[i] = fib[i-1] + fib[i-2];
    printf("Fibonacci series: ");
    for (i = 0; i < n; i++)
        printf("%d ", fib[i]);
    return 0;
}

Dynamic Memory Allocation and Average Calculation

Exam Source: 2024 Q7(c) / 2025 Q6(a) — Repeated both years!

Note: malloc returns void*, cast to int*. Always free() after use. If malloc returns NULL, memory allocation failed.

#include <stdio.h>
#include <stdlib.h&

Longest Substring Without Repeating Characters

This problem involves finding the length of the longest substring in a given string that does not contain any repeating characters. A common approach uses a sliding window technique with a Set to efficiently track unique characters.

Strategy:

• Utilize a Set to store characters within the current window.
• Iterate through the string with a right pointer, adding characters to the Set.
• If a duplicate character is encountered, move the left pointer forward, removing characters from the Set, until the duplicate is no longer present.
• At each step, update the maximum length found.

Java Implementation Snippet

class Solution {
    public int findLongestSubstringWithoutRepeatingCharacter(String str) {
        Set&

Assembly Language Fundamentals: Key Concepts and Definitions

1. Clock Frequency and Cycle Time

A clock that oscillates 1 million times per second (1 MHz) produces a clock cycle duration of $10^{-6}$ seconds (1 microsecond).

2. General-Purpose Registers (8-bit, 16-bit, and 32-bit Access)

The general-purpose registers that can be accessed in 8 bits, 16 bits, and 32 bits are: EAX, EBX, ECX, and EDX.

3. Purpose of EAX and ECX Registers

These registers serve specific roles in CPU operations:

• EAX – Accumulator: Automatically used by multiplication and division instructions. It is often referred to as the extended accumulator register.
• ECX – Loop Counter: The CPU automatically uses ECX as a counter for loop instructions.

4. Reserved Words and Identifiers