During the Implementation Stage of the Software Development Life Cycle (SDLC), different types of testing are performed to verify that the software functions correctly and meets the specified requirements.

1. Unit Testing

Unit Testing is performed to test individual modules, functions, or classes independently. It is usually conducted by developers to ensure that each unit works correctly.

2. Integration Testing

Integration Testing verifies that multiple modules work together correctly after integration. It checks the interfaces and data flow between modules.

3. System Testing

System Testing evaluates the complete integrated software system to ensure that it meets all functional and non-functional requirements.

4. Acceptance Testing

Acceptance Testing is performed by customers or end users to verify that the software satisfies business requirements and is ready for deployment. It includes User Acceptance Testing (UAT).

These testing types ensure that the software is reliable, error-free, and ready for deployment by identifying defects at different levels of the implementation stage.

Inheritance is one of the fundamental concepts of Object-Oriented Programming (OOP). It allows a new class (Derived Class) to inherit the properties and methods of an existing class (Base Class). This promotes Code Reusability, reduces code duplication, and improves maintainability.

Types of Inheritance

1. Single Inheritance
A single Derived Class inherits from one Base Class.

Example:
Animal → Dog

2. Multiple Inheritance
A single Derived Class inherits from more than one Base Class. This type is supported in C++ but not directly in Java.

Example:
Teacher + Researcher → Professor

3. Multilevel Inheritance
A class inherits from another derived class, forming a chain of inheritance.

Example:
Animal → Mammal → Dog

4. Hierarchical Inheritance
Multiple Derived Classes inherit from a single Base Class.

Example:
Animal → Dog, Cat, Cow

5. Hybrid Inheritance
A combination of two or more inheritance types (such as Multiple and Multilevel Inheritance). It is commonly implemented using virtual inheritance in C++.

Example:
Combination of Single + Multiple + Multilevel Inheritance.

Inheritance improves Code Reusability, reduces redundancy, simplifies maintenance, and supports efficient software development by allowing classes to reuse existing features.

Enqueue is the operation of inserting a new element into a Queue. Since a Queue follows the FIFO (First In, First Out) principle, a new element is always inserted at the Rear end of the Queue.

Steps of Enqueue Operation

Step 1: Check whether the Queue is full.
Step 2: If the Queue is full, display "Queue Overflow" and stop the operation.
Step 3: If the Queue is empty, set Front = Rear = 0.
Step 4: Otherwise, increment the Rear pointer by 1.
Step 5: Insert the new element at Queue[Rear].
Step 6: End the operation.

Algorithm (Enqueue)

START
If Rear = MAX − 1
Print "Queue Overflow"
Else
If Front = -1
Front = Rear = 0
Else
Rear = Rear + 1
Queue[Rear] = Item
END

Algorithm Complexity measures the amount of Time and Memory required by an algorithm to solve a problem. It helps compare different algorithms and select the most efficient one.

Factors Affecting Algorithm Complexity

1. Time Complexity
Time Complexity measures the amount of time an algorithm takes to execute as the input size increases. It is commonly expressed using Big-O Notation, such as O(1), O(log n), O(n), O(n log n), and O(n²).

2. Space Complexity
Space Complexity measures the amount of memory required by an algorithm during execution. It includes memory used for variables, data structures, recursion, and temporary storage.

3. Input Size (n)
The execution time and memory usage usually increase as the input size (n) becomes larger.

4. Type of Operations
Algorithms performing complex operations such as nested loops, recursion, or repeated computations generally have higher complexity than algorithms using simple operations.

5. Data Structure Used
The choice of data structure (such as Array, Linked List, Stack, or Hash Table) significantly affects the algorithm's performance.

The efficiency of an algorithm mainly depends on its Time Complexity and Space Complexity. Selecting appropriate algorithms and data structures helps improve overall system performance.

A Transaction is a sequence of one or more SQL statements executed as a single logical unit of work. A transaction must be terminated using SQL transaction control statements.

SQL Statements to End a Transaction

COMMIT saves the transaction permanently, ROLLBACK cancels the transaction, and SAVEPOINT allows partial rollback within a transaction.

#include <iostream>
using namespace std;

int main()
{
    float hourlyWage, regularHours, overtimeHours;
    float overtimePay, totalPay;

    cout << "Enter Hourly Wage: ";
    cin >> hourlyWage;

    cout << "Enter Regular Hours: ";
    cin >> regularHours;

    cout << "Enter Overtime Hours: ";
    cin >> overtimeHours;

    overtimePay = overtimeHours * 1.5 * hourlyWage;
    totalPay = (regularHours * hourlyWage) + overtimePay;

    cout << "Total Weekly Pay = " << totalPay;

    return 0;
}

Example

Hourly Wage = 200
Regular Hours = 40
Overtime Hours = 10
Total Weekly Pay = (40 × 200) + (10 × 1.5 × 200) = 8000 + 3000 = 11000

Common Banking Software Used in Bangladesh

• Temenos T24 (Transact)
• Oracle FLEXCUBE
• Finacle (Infosys)
• Flora Banking Solution
• PC Bank 2000
• Bank Ultimus
• CBS (Core Banking System)
• Ababil Banking Solution

Essential Features of Banking Software and Apps

• Secure User Authentication (Password, OTP, MFA)
• Core Banking Services (Deposit, Withdrawal, Transfer)
• Real-Time Transaction Processing
• Internet and Mobile Banking Support
• Fund Transfer (BEFTN, RTGS, NPSB, Binimoy)
• Account Balance and Transaction History
• Bill Payment and Mobile Recharge
• Loan and Deposit Management
• Customer Management (KYC)
• Data Encryption and Backup
• Audit Log and Transaction Tracking
• High Availability and Disaster Recovery

RFID (Radio Frequency Identification) is a wireless technology that uses Radio Waves to identify and track objects, people, or animals automatically without physical contact. It is widely used in Supply Chain Management, Toll Collection, Inventory Management, and Access Control.

Main Components of RFID

1. RFID Tag: Attached to an object and stores a unique identification number (ID).
2. RFID Reader: Sends and receives radio signals to communicate with the RFID Tag.
3. Antenna: Transmits and receives radio waves between the Reader and the Tag.
4. Computer/Database: Receives the data from the Reader and processes or stores the information.

Working Principle of RFID

Step 1: The RFID Reader transmits Radio Waves through its Antenna.
Step 2: When an RFID Tag comes within the Reader's range, it receives the radio signal.
Step 3: The RFID Tag sends its stored ID back to the Reader.
Step 4: The RFID Reader forwards the received data to the Computer/Database.
Step 5: The system verifies, processes, and stores the information for further use.

Applications

• Supply Chain Management
• Toll Collection System
• Inventory Management
• Access Control
• Asset Tracking

LTE (Long Term Evolution) is a 4G wireless communication technology. An LTE network consists of several network elements that work together to provide high-speed voice and data communication.

List of LTE Network Elements

The main LTE network elements are UE, eNodeB, MME, S-GW, P-GW, HSS, and PCRF. Together, they provide reliable, secure, and high-speed mobile communication.

SQL (Structured Query Language) is used to create, manage, manipulate, and control databases. Its main components are DDL (Data Definition Language), DML (Data Manipulation Language), and DCL (Data Control Language).

1. DDL (Data Definition Language)

DDL commands are used to create and modify the structure of database objects such as tables, views, and indexes.

2. DML (Data Manipulation Language)

DML commands are used to insert, retrieve, update, and delete data stored in database tables.

3. DCL (Data Control Language)

DCL commands are used to control user access and permissions in a database.

Recursion is a programming technique in which a Function calls itself repeatedly until a Base Case is reached. It is commonly used to solve problems that can be divided into smaller subproblems.

Recursive Algorithm

Algorithm Factorial(n)
BEGIN
If n = 0 or n = 1 Then
Return 1
Else
Return n × Factorial(n − 1)
END

Example

Input: n = 5
Factorial(5)
= 5 × Factorial(4)
= 5 × 4 × Factorial(3)
= 5 × 4 × 3 × Factorial(2)
= 5 × 4 × 3 × 2 × Factorial(1)
= 5 × 4 × 3 × 2 × 1
= 120

Major Types of Operating System (OS) Scheduling

Answer:

OS Scheduling is the process of selecting which process will execute on the CPU. It is a key concept of Multiprogramming because it improves CPU utilization and system performance.

Major Types of OS Scheduling

The Long-Term Scheduler controls the degree of multiprogramming, the Short-Term Scheduler allocates the CPU, and the Medium-Term Scheduler manages memory efficiently through swapping.

(i) Convert (10010.101)₂ to Decimal

Binary Number = (10010.101)₂

Integer Part:
= (1 × 2⁴) + (0 × 2³) + (0 × 2²) + (1 × 2¹) + (0 × 2⁰)
= 16 + 0 + 0 + 2 + 0
= 18

Fractional Part:
= (1 × 2^-1) + (0 × 2^-2) + (1 × 2^-3)
= 0.5 + 0 + 0.125
= 0.625

Therefore,
(10010.101)₂ = (18.625)₁₀

(ii) Convert (543)₁₀ to Hexadecimal

Successive Division by 16:

Read the remainders from bottom to top:

(543)₁₀ = (21F)₁₆

Insertion Sort is a simple sorting algorithm that builds the sorted array one element at a time. It repeatedly takes an element and inserts it into its correct position in the already sorted portion of the array.

#include <iostream>
using namespace std;

int main()
{
    int n, i, j, key;

    cout << "Enter number of elements: ";
    cin >> n;

    int a[n];

    cout << "Enter elements: ";
    for(i = 0; i < n; i++)
        cin >> a[i];

    for(i = 1; i < n; i++)
    {
        key = a[i];
        j = i - 1;

        while(j >= 0 && a[j] > key)
        {
            a[j + 1] = a[j];
            j--;
        }

        a[j + 1] = key;
    }

    cout << "Sorted Array: ";

    for(i = 0; i < n; i++)
        cout << a[i] << " ";

    return 0;
}

Example

Input: 5 4 2 7 1 3
Output: 1 2 3 4 7

Transmission Control Protocol (TCP) is a connection-oriented Transport Layer protocol that provides reliable, ordered, and error-free data transmission between devices over an unreliable network such as the Internet.

Functions of TCP

1. Connection Establishment
TCP establishes a reliable connection between the sender and receiver using the Three-Way Handshake before transmitting data.

2. Reliable Data Delivery
TCP uses Sequence Numbers and Acknowledgments (ACK) to ensure that all packets are delivered correctly.

3. Error Detection and Recovery
TCP uses a Checksum to detect transmission errors. If an error or packet loss occurs, the lost packet is retransmitted.

4. Flow Control
TCP uses the Sliding Window mechanism to control the amount of data sent, preventing the receiver from being overwhelmed.

5. Congestion Control
TCP controls network congestion using techniques such as Slow Start, Congestion Avoidance, and Fast Recovery.

6. Ordered Data Delivery
TCP ensures that data is delivered to the application in the same order in which it was sent.

7. Duplicate Packet Elimination
TCP identifies and discards duplicate packets using Sequence Numbers.

8. Connection Termination
After communication is complete, TCP gracefully closes the connection using the FIN/ACK process