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

Automated Data Extraction Using LangChain and Cohere

This script demonstrates how to leverage LangChain, Cohere, and the Wikipedia API to extract structured information about institutions. By using Pydantic, we ensure the extracted data follows a strict schema for better reliability.

Required Libraries and Data Models

First, we import the necessary modules and define our data structure using a Pydantic model to store institution details such as the founder, founding year, and employee count.

from langchain_community.llms import Cohere
from langchain.prompts import PromptTemplate
from langchain_core.runnables import RunnableLambda
from pydantic import BaseModel
import wikipediaapi

class InstitutionDetails(BaseModel):
    founder: str
    founded:

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&