Difference between Process and Thread
Process
A process is an independent program in execution. It has its own memory space, resources, and execution context.
• Has separate address space
• More resource consumption
• Inter-process communication is complex
• Slower context switchingThread
A thread is a lightweight unit of execution within a process. Multiple threads share the same memory and resources of a process.
• Shares address space with other threads
• Less resource consumption
• Communication is easier (shared memory)
• Faster context switching

Key Differences
• Process is heavy-weight, thread is light-weight
• Process has its own memory, thread shares memory
• Process is isolated, thread is not

Function Overloading
Function overloading is a feature of Object-Oriented Programming where multiple functions have the same name but different parameter lists (different number or type of parameters). It is resolved at compile time.
Example (Function Overloading in C++)

int add(int a, int b) {
    return a + b;
}
double add(double a, double b) {
    return a + b;
}

Here, the function add() is overloaded to work with both integers and doubles.

Operator Overloading
Operator overloading allows existing operators (such as +, -, *, etc.) to be redefined for user-defined data types. It makes programs more readable and intuitive.

Example (Operator Overloading in C++)

class Complex {
public:
    int real;
    Complex(int r) { real = r; }

    Complex operator + (Complex obj) {
        return Complex(real + obj.real);
    }
};

Here, the + operator is overloaded to add two Complex objects.

How Quick Sort is Implemented
Quick Sort is a divide-and-conquer sorting algorithm. It works by selecting a pivot element, partitioning the array so that elements smaller than the pivot are placed on the left and larger elements on the right, and then recursively applying the same process to the left and right subarrays until the entire array is sorted.

Main Steps
1) Choose a pivot element (first, last, middle, or random).
2) Partition the array around the pivot.
3) Recursively apply Quick Sort on left and right subarrays.

Time Complexity of Quick Sort
Best Case: O(n log n) (balanced partition).
Average Case: O(n log n).
Worst Case: O(n²) (when pivot is always smallest or largest, e.g., already sorted array).

Space Complexity
O(log n) (recursive stack, average case).

Normalization
Normalization is a database design process used to organize data into tables in such a way that data redundancy is reduced and data integrity is improved. It involves dividing a database into smaller, well-structured tables and defining proper relationships between them.

Why Normalization is Needed
• To remove duplicate (redundant) data
• To avoid update, insert, and delete anomalies
• To ensure data consistency and accuracy
• To improve database structure and maintenance
• To save storage space

Weak Entity Set
A weak entity set is an entity that cannot be uniquely identified by its own attributes alone. It depends on a strong (owner) entity for its identification and existence. A weak entity does not have a primary key of its own.

Primary Key Generation for a Weak Entity
The primary key of a weak entity is formed by combining:
• The primary key of the strong (owner) entity
• The partial key (discriminator) of the weak entity

This combined key uniquely identifies each weak entity instance.

Difference between IPv4 and IPv6
IPv4
• Address length is 32 bits
• Address format is dotted decimal (e.g., 192.168.1.1)
• Limited address space (≈4.3 billion)
• Uses NAT to overcome address shortage
• Header is simpler but less efficient
• Supports broadcast

IPv6
• Address length is 128 bits
• Address format is hexadecimal (e.g., 2001:db8::1)
• Very large address space
• NAT is not required
• Header is more efficient and simplified
• No broadcast, uses multicast and anycast

Secret Key Encryption (Symmetric Encryption)
Secret key encryption is a method where the same key is used for both encryption and decryption of data. Both sender and receiver must share this secret key securely before communication.

Example: AES, DES

Public Key Encryption (Asymmetric Encryption)
Public key encryption uses two different keys: a public key for encryption and a private key for decryption. The public key is shared openly, while the private key is kept secret by the receiver.

Example: RSA, ECC

Difference between Broadband Wi-Fi and Wi-MAX
Broadband Wi-Fi
• Short-range wireless communication technology
• Coverage area is small (home, office, hotspot)
• Based on IEEE 802.11 standards
• Uses unlicensed frequency bands
• Lower installation cost
• Commonly used for local internet access

Wi-MAX
• Long-range wireless broadband technology
• Coverage area is large (city or metropolitan area)
• Based on IEEE 802.16 standard
• Uses licensed and unlicensed bands
• Higher infrastructure cost
• Used for wide-area broadband internet access

Deadlock in the Dining-Philosophers Problem
The dining-philosophers problem describes a situation where several philosophers sit around a circular table, and each philosopher needs two forks (left and right) to eat. A deadlock occurs when each philosopher picks up one fork (usually the left one) and waits indefinitely for the other fork, which is held by another philosopher.

Since no philosopher is willing to release the fork they already have, all philosophers remain waiting forever. This situation satisfies all four deadlock conditions: mutual exclusion, hold and wait, no preemption, and circular wait, causing the system to enter a deadlock state.

Message Confidentiality
Message confidentiality ensures that only authorized parties can read the message. It protects data from being accessed by unauthorized users, usually achieved through encryption.

Message Integrity
Message integrity ensures that the message has not been altered during transmission. It verifies that the received data is exactly the same as the sent data, typically using hash functions or message authentication codes (MACs).

Differences
• Confidentiality protects data from being read
• Integrity protects data from being modified
• Confidentiality uses encryption
• Integrity uses hashing or MACs

Can One Exist Without the Other?
Yes. A message can be confidential without integrity (encrypted but modified) and can have integrity without confidentiality (data is readable but tamper-proof).