ETEA Engineering Test Computer Science Syllabus

What is the quick method to convert between binary and hexadecimal?

Each hexadecimal digit equals exactly 4 binary bits. To convert, group binary digits in sets of 4 (from the right) and replace each group with its hex digit, or expand each hex digit into 4 bits.

How many bits make one byte, and what is a byte typically used to store?

$1$ byte $=8$ bits. A byte typically stores one character (e.g., a letter, digit, or symbol).

List the storage units in increasing order from bit to terabyte with their relationships.

$8\text{ bits}=1\text{ byte}$; $1024\text{ bytes}=1\text{ KB}$; $1024\text{ KB}=1\text{ MB}$; $1024\text{ MB}=1\text{ GB}$; $1024\text{ GB}=1\text{ TB}$ (using $1024=2^{10}$).

What is ASCII and how many characters can standard ASCII represent?

ASCII (American Standard Code for Information Interchange) is a character-encoding standard. Standard 7-bit ASCII represents $2^{7}=128$ characters; extended 8-bit ASCII represents $256$ characters.

Differentiate between guided (wired) and unguided (wireless) transmission media, with examples.

Guided media transmit signals through a physical cable/path: twisted-pair, coaxial cable, optical fibre. Unguided media transmit signals through air/space without a physical conductor: radio waves, microwaves, infrared, satellite.

Why is optical fibre faster and more reliable than copper cable?

Optical fibre transmits data as pulses of light through glass/plastic, giving very high bandwidth and speed, low signal attenuation over long distances, and immunity to electromagnetic interference (unlike copper which carries electrical signals).

Compare the three data transmission modes: simplex, half-duplex, and full-duplex.

Simplex: data flows in one direction only (e.g., keyboard to CPU, TV broadcast). Half-duplex: data flows both ways but only one direction at a time (e.g., walkie-talkie). Full-duplex: data flows in both directions simultaneously (e.g., telephone call).

Define network topology and name the common types.

Network topology is the physical or logical arrangement/layout of devices (nodes) in a network. Common types: bus, star, ring, mesh, tree, and hybrid.

Describe the star topology and one advantage and one disadvantage.

In a star topology all nodes connect to a central device (hub/switch). Advantage: failure of one cable/node does not affect others; easy to manage. Disadvantage: if the central hub fails, the entire network goes down.

Describe the bus topology and a major disadvantage.

In a bus topology all devices share a single common backbone cable. Disadvantage: a fault or break in the main cable brings down the whole network, and performance drops as more nodes are added.

In a mesh topology with $n$ nodes, how many cables (links) are needed for full connection?

Number of links $=\dfrac{n(n-1)}{2}$, since every node connects directly to every other node.

What is the difference between LAN, MAN, and WAN?

LAN (Local Area Network) covers a small area like a building/office. MAN (Metropolitan Area Network) covers a city. WAN (Wide Area Network) covers very large areas such as countries or the globe; the Internet is the largest WAN.

What is the Internet?

The Internet is a global network of interconnected computer networks that communicate using standard protocols (TCP/IP) to share information and resources worldwide.

What does the protocol TCP/IP stand for and what is its role?

TCP/IP stands for Transmission Control Protocol / Internet Protocol. It is the fundamental suite of protocols that governs how data is broken into packets, addressed, transmitted, routed, and reassembled across the Internet.

What is the difference between HTTP and HTTPS?

HTTP (HyperText Transfer Protocol) transfers web pages between server and browser in plain text. HTTPS is the secure version that encrypts data using SSL/TLS, protecting it from interception.

State the purpose of the protocols FTP, SMTP, and IP.

FTP (File Transfer Protocol) transfers files between computers. SMTP (Simple Mail Transfer Protocol) sends email. IP (Internet Protocol) provides addressing and routing of data packets between hosts.

What is an IP address?

An IP address is a unique numerical label assigned to each device on a network, used to identify and locate it for communication. IPv4 uses a 32-bit address written as four numbers (e.g., $192.168.0.1$).

What is a database and a DBMS?

A database is an organized collection of related data stored for easy access, management, and updating. A DBMS (Database Management System) is software used to create, store, manage, and retrieve data in a database (e.g., MySQL, Oracle, MS Access).

Define the terms field, record, and table in a database.

A field (column) is a single attribute/category of data (e.g., Name). A record (row) is a complete set of related fields describing one entity (e.g., one student). A table is a collection of related records organized in rows and columns.

What is a primary key in a database?

A primary key is a field (or set of fields) that uniquely identifies each record in a table. It must be unique and cannot be null (empty).

What is an algorithm?

An algorithm is a finite, step-by-step set of well-defined instructions to solve a particular problem or perform a task, with a clear beginning and end.

What is a flowchart and what do the oval, rectangle, parallelogram, and diamond symbols represent?

A flowchart is a diagrammatic (graphical) representation of an algorithm. Oval = Start/Stop (terminal); Rectangle = process/calculation; Parallelogram = input/output; Diamond = decision/condition.

What are the three basic control (programming) constructs?

(1) Sequence - statements executed in order; (2) Selection (decision/branching) - choosing a path using if/else or switch; (3) Iteration (looping/repetition) - repeating statements using loops.

What is the difference between selection and iteration constructs?

Selection chooses between alternative paths based on a condition (executed once per decision), e.g., if-else. Iteration repeats a block of statements multiple times while/until a condition holds, e.g., for, while loops.

What is the key difference between a while loop and a do-while loop in C?

A while loop is entry-controlled: it checks the condition before executing the body, so the body may run zero times. A do-while loop is exit-controlled: it executes the body first then checks the condition, so the body always runs at least once.

Write the general syntax of a for loop in C and name its three parts.

$\texttt{for(initialization; condition; update) \{ statements \}}$. The three parts are: initialization (set start value), condition (tested before each iteration), and update (increment/decrement).

What is the difference between the if-else statement and the switch statement in C?

if-else evaluates Boolean conditions/ranges and can handle any relational logic. switch selects among multiple cases by matching a single variable against constant values; it is cleaner for many equality comparisons but cannot test ranges directly.

What is a function in programming and what are its advantages?

A function is a named, self-contained block of code that performs a specific task and can be called whenever needed. Advantages: code reusability, modularity, easier debugging, and reduced program length.

In C, distinguish between a function's arguments (parameters) and its return value.

Arguments/parameters are the input values passed into a function for it to process. The return value is the single result the function sends back to the caller using the $\texttt{return}$ statement.

What is the role of the main() function in a C program?

$\texttt{main()}$ is the entry point of every C program; program execution always begins from $\texttt{main()}$. It typically returns an integer (e.g., $\texttt{return 0;}$) indicating successful execution.

Name the basic data types in C and what each stores.

$\texttt{int}$ stores whole numbers; $\texttt{float}$ and $\texttt{double}$ store real (decimal) numbers; $\texttt{char}$ stores a single character; $\texttt{void}$ represents no value/type.

What are the standard input and output functions in C, and which header file declares them?

$\texttt{scanf()}$ reads input and $\texttt{printf()}$ displays output. Both are declared in the header file $\texttt{stdio.h}$, included using $\texttt{\#include <stdio.h>}$.