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

Designing Forms and Reports

• Process of designing forms and reports
• General guidelines for formatting forms and reports

Designing Interfaces and Dialogues

• Process of designing interfaces and dialogues
• General guidelines for interface design
• Guidelines for the design of human-computer dialogues

Designing Web and Mobile Interfaces

• General guidelines
• Principles of mobile interface design

Understanding Forms and Reports

What is a Form?

A form is a business document that contains predefined data and may include areas where additional data is to be filled in. Traditionally, forms are paper-based. Today, the layout of almost any paper-based form can be displayed on a video display. Form interaction is a standard method for gathering and displaying information... Continue reading "Effective Interface and Report Design Strategies" »

Boston Housing Data Analysis

library(mlbench)
install.packages("dplyr")
library(dplyr)
library(ggplot2)
library(reshape2)
data("BostonHousing")
housing <- BostonHousing
str(housing)

housing %>%   ggplot(aes(x = medv)) +
  stat_density() +
  labs(x = "Median Value ($1000s)", y = "Density", title = "Density Plot of Median Value House Price in Boston") +
  theme_minimal()

summary(housing$medv)

housing %>%   select(c(crim, rm, age, rad, tax, lstat, medv)) %>%   melt( id.vars = "medv") %>%   ggplot(aes(x = value, y = medv, colour = variable)) +
  geom_point(alpha = 0.7) +
  stat_smooth(aes(colour = "black")) +
  facet_wrap(~variable, scales = "free", ncol = 2) +
  labs(x = "Variable Value", y = "Median House Price ($1000s)") +
  theme_minimal(

Vulnerabilities in Von Neumann Architecture

The system architect of the von Neumann is the way that it can allow direct memory access to the low level languages like C and C++.

If the program goes and tries to access the memory out of bound by allocating code injection to the system, it allows the system to access the memory out of the stack which causes buffer overflow and the attacker can access the other memory from the allocated stack. This way an attacker can get access to the system. Therefore von Neumann architecture is vulnerable to code injection, the effect of the buffer overflow.

Understanding Threats and Attacks

Threats

• It is a potential security violation that might exploit vulnerability of the system or assets.
• Threats can be accidental,

C++ Fundamentals

Let's learn about basic C++

Source: GeeksforGeeks

Loops in C++

For Loop

#include <iostream>
using namespace std;
int main() {
    for(int i = 1; i <= 5; i++) {
        cout << "Good morning \n";
    }
    return 0;
}

While Loop

#include <iostream>
using namespace std;
int main() {
    int i = 0; // Initialization
    while(i < 5) { // Test expression
        cout << "Good morning\n";
        i++; // Update expression
    }
    return 0;
}

Do-While Loop

#include <iostream>
using namespace std;
int main() {
    int i = 2; // Initialization
    do {
        cout << "Good morning\n";
        i++; // Update expression
    } while(i < 1); // Test expression
    return 0;
}

C++ Interview Questions

1.

JavaScript Cheat Sheet

JavaScript Arrays

var cars = ["Mercedes", "Tesla","Volvo"];

• pop(): Removes the last element of an array.
• push(): Adds a new element at the end of an array.
• concat(): Joins various arrays into a single array.
• reverse(): Reverses the order of elements in an array.
• indexOf(): Returns the first index of a given element in an array.
• lastIndexOf(): Returns the last index of a given element in an array.
• join(): Combines elements of an array into a single string.
• sort(): Sorts array elements based on a condition.

Global Functions

These functions are built-in to every browser that runs JavaScript:

• parseFloat(): Parses the argument and returns a floating-point number.
• parseInt(): Parses the argument and returns an integer.
• Number(): Returns a

Pentium P5 Processor Pipelining Stages

The Pentium processor, specifically the Pentium Classic (P5) architecture, featured a five-stage pipeline. The five stages of pipelining in the Pentium processor are as follows:

1. Instruction Fetch (IF): This stage is responsible for fetching instructions from the memory. The instruction pointer determines the next instruction to be fetched, and the instruction cache is utilized to improve performance by storing frequently accessed instructions.
2. Instruction Decode (ID): In this stage, the fetched instruction is decoded. The opcode and operands are identified, and any necessary data dependencies or control hazards are resolved.
3. Execution (EX): The execution stage performs the actual computation or operation specified

Essential Web and Software Terminology

Web Navigation and Structure

• External Hyperlink

  A hyperlink that opens a webpage located on a remote computer. External hyperlinks provide the links that tie the Web together and rely on HTML anchor tags.

• Back Button

  A basic control used across various technologies. In a web browser, a back button allows an end user to navigate to a previously viewed webpage. A back button is also a feature of smartphone software and other consumer-oriented technologies.

• Navigation Structure

  When using navigation requests, for each BSP application, determine the initial page, the navigation methods, and the target pages in a table with navigation paths.

• Refresh

  An act or function of updating the display on a screen.

Web Elements

File Management

File management is the system an operating system uses to organize and keep track of data. The operating system stores data in units called files, determines how files are stored, efficiently uses available storage space, creates a record of all file usage, and carries out every task related to files and folders.

File names typically have this structure:

filename.extension

Task and User Management

Task Management

Task management is the part of the operating system that controls the running of one or more programs on a computer simultaneously. Today's widely used operating systems support multitasking, allowing multiple tasks to run concurrently, taking turns using the computer's resources.

User Management

With user management, the operating... Continue reading "Understanding Operating Systems: File, Task, and User Management" »

Understanding Digital Certificates

A digital certificate (or electronic certificate) is a computer file generated by a certification authority that associates identity data with a natural person, organization, or company, confirming their digital identity on the internet.

What Is Code Signing?

Code signing is a method that uses a certificate-based digital signature to sign executables and scripts. This process verifies the author’s identity and ensures the code has not been altered or corrupted since it was signed. This helps users and software determine whether an application can be trusted.

HTTPS and SSL Encryption

HTTPS (Hypertext Transfer Protocol Secure) is an extension of HTTP that utilizes SSL (Secure Sockets Layer) encryption. It creates... Continue reading "Digital Certificates, HTTPS, and Spyware Protection Explained" »