HEC USAT Computer Science Syllabus

What is the difference between a Boolean and an integer data type?

A Boolean stores only two values, true or false (1 or 0), while an integer stores whole numbers (positive, negative, or zero) without decimals.

What is a control structure in programming?

A control structure determines the order in which statements are executed. The three main types are sequence, selection (decision), and iteration (loops).

What is the difference between selection and iteration control structures?

Selection (e.g., if-else, switch) chooses which block of code to execute based on a condition. Iteration (loops like for, while) repeats a block of code multiple times.

Differentiate between a 'while' loop and a 'for' loop.

A 'for' loop is used when the number of iterations is known in advance. A 'while' loop is used when the number of iterations is unknown and depends on a condition being true.

What is the difference between a 'while' loop and a 'do-while' loop?

A 'while' loop checks the condition before executing the body (may run zero times). A 'do-while' loop checks the condition after executing the body, so it always runs at least once.

What is an infinite loop and what causes it?

An infinite loop is a loop that never terminates because its exit condition never becomes false. It is usually caused by a missing or incorrect update to the loop control variable.

What is the purpose of an if-else statement?

An if-else statement executes one block of code if a condition is true and a different block if the condition is false, allowing the program to make decisions.

What is a function in programming?

A function is a named, reusable block of code that performs a specific task. It can take inputs (parameters), perform operations, and return a result, helping reduce code repetition.

What is the difference between a function's parameter and an argument?

A parameter is the variable named in the function definition that receives a value. An argument is the actual value passed to the function when it is called.

What is an array in programming?

An array is a data structure that stores a collection of elements of the same data type in contiguous memory locations, accessed using an index.

In most programming languages, what is the index of the first element of an array?

The first element of an array is at index 0 (zero-based indexing). So an array of size n has indices from 0 to n-1.

What is the main advantage of using functions in a program?

Functions promote code reusability, make programs modular and easier to read, reduce repetition, and simplify debugging and maintenance.

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.

What is a flowchart?

A flowchart is a graphical or diagrammatic representation of an algorithm or process using standard symbols connected by arrows to show the flow of control.

What flowchart symbol is used for a decision, and what shape is it?

A decision in a flowchart is represented by a diamond (rhombus) shape, which has one entry point and two or more exit paths (e.g., yes/no).

What flowchart symbol represents the start or end of a process?

The terminal (start/stop) symbol is an oval or rounded rectangle, used to indicate the beginning or end of a flowchart.

What flowchart symbol is used for a process or calculation step?

A rectangle is used to represent a process, action, or calculation step in a flowchart.

What is pseudocode?

Pseudocode is an informal, high-level description of an algorithm using plain language mixed with programming-like structure, without following the syntax of any specific programming language.

How many bits are in one byte, and what is the smallest unit of data?

One byte equals 8 bits. The bit (binary digit, 0 or 1) is the smallest unit of data in a computer.

Arrange these units from smallest to largest: Megabyte, Kilobyte, Gigabyte, Byte.

Byte < Kilobyte (KB) < Megabyte (MB) < Gigabyte (GB). Each unit is approximately 1024 times the previous one.

What is ASCII?

ASCII (American Standard Code for Information Interchange) is a character encoding standard that represents text characters as numbers, typically using 7 or 8 bits per character.

How is an image represented digitally in a computer?

An image is represented as a grid of pixels, where each pixel's color is stored as a binary number. More bits per pixel allow more colors (color depth).

What is a database?

A database is an organized collection of related data stored electronically so it can be easily accessed, managed, and updated.

What is a DBMS?

A DBMS (Database Management System) is software that allows users to create, store, retrieve, update, and manage data in a database (e.g., MySQL, Oracle, MS Access).

In a database, what is the difference between a field and a record?

A field is a single column representing one attribute (e.g., Name). A record is a single row containing a complete set of related fields about one item (e.g., one student's full data).

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 cannot contain duplicate or null values.

In a spreadsheet, what is a cell and how is it referenced?

A cell is the intersection of a row and a column where data is entered. It is referenced by its column letter and row number (e.g., B5).

Write the spreadsheet formula to add the values in cells A1 to A10.

=SUM(A1:A10). The colon denotes a range, and SUM adds all values within that range.

What is the difference between a LAN and a WAN?

A LAN (Local Area Network) covers a small geographic area like a building or office. A WAN (Wide Area Network) covers a large geographic area, like a country, and connects multiple LANs (the Internet is the largest WAN).

What is the difference between the Internet and the World Wide Web (WWW)?

The Internet is the global network of interconnected computers (the infrastructure). The World Wide Web is a service that runs on the Internet, consisting of websites and web pages accessed via browsers using HTTP.