10+ St Joseph's Academy Interview Questions and Answers

The system call that creates a separate connection is fork()

• fork() is a system call in Unix-like operating systems that creates a new process by duplicating the existing process

• The new process created by fork() is called the child process, while the original process is called the parent process

• fork() is commonly used in network programming to create separate connections for handling multiple clients

TCP supports four types of connection release: active close, passive close, simultaneous close, and abortive close.

• Active close: Client initiates the connection release process by sending a FIN packet.

• Passive close: Server initiates the connection release process by sending a FIN packet.

• Simultaneous close: Both client and server send FIN packets to each other simultaneously.

• Abortive close: Connection is terminated abruptly without following the normal connection release proce...read more

Use double pointer to dynamically allocate memory for array of strings in C.

• Declare a double pointer to hold the 2D array of strings.

• Allocate memory for the rows first using malloc.

• Then allocate memory for each string in the row using malloc.

• Assign values to the strings in the array.

• Example: char **array = malloc(rows * sizeof(char *));

• Example: array[i] = malloc(strlen(str) + 1); strcpy(array[i], str);

Different protocols used in the transport layer include TCP, UDP, SCTP, and DCCP.

• TCP (Transmission Control Protocol) - reliable, connection-oriented protocol used for most internet communication

• UDP (User Datagram Protocol) - connectionless protocol used for applications where speed is more important than reliability

• SCTP (Stream Control Transmission Protocol) - supports multiple streams of data, used for telecommunication signaling

• DCCP (Datagram Congestion Control Protocol) - ...read more

epoll_wait() system call waits for events on an epoll instance

• Used in Linux for I/O event notification

• Blocks until one or more file descriptors become ready

• Returns the number of file descriptors ready for I/O operations

The MAC layer uses protocols like CSMA/CA, CSMA/CD, and TDMA to manage access to the network.

• CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) is used in wireless networks to avoid collisions.

• CSMA/CD (Carrier Sense Multiple Access with Collision Detection) is used in wired networks to detect and handle collisions.

• TDMA (Time Division Multiple Access) is used in networks where devices are assigned specific time slots to transmit data.

TCP is a connection-oriented protocol that ensures reliable data delivery, while UDP is a connectionless protocol that focuses on speed.

• TCP is reliable and ensures data delivery by establishing a connection before sending data.

• UDP is faster but less reliable as it does not establish a connection before sending data.

• TCP is used for applications that require high reliability and error correction, such as web browsing and email.

• UDP is used for real-time applications like online ...read more

Virtual functions in C++ are functions that can be overridden in derived classes, allowing for polymorphic behavior.

• Virtual functions are declared using the 'virtual' keyword in the base class.

• They are used to achieve runtime polymorphism in C++.

• Derived classes can override the virtual functions defined in the base class.

• Example: class Base { public: virtual void display() { cout << 'Base class display function'; } }; class Derived : public Base { public: void display() overr...read more

ICMP is a protocol used for error reporting, diagnostics, and network management in IP networks.

• ICMP is used to report errors in packet delivery

• It is used for network diagnostics and troubleshooting

• ICMP messages are encapsulated within IP packets

• Examples include ping (echo request/reply) and traceroute

Virtual base classes are classes that are inherited virtually to avoid multiple instances of the same base class in a derived class hierarchy.

• Virtual base classes are used in multiple inheritance to prevent the Diamond Problem.

• They are declared with the 'virtual' keyword in the base class.

• When a class inherits a virtual base class, the most derived class is responsible for initializing the virtual base class.

• Example: class A is a virtual base class for classes B and C. If D i...read more

ARP (Address Resolution Protocol) is a protocol used to map an IP address to a MAC address in a local network.

• ARP is used to resolve IP addresses to MAC addresses in a local network.

• It operates at the data link layer of the OSI model.

• ARP requests are broadcasted to all devices on the network.

• Example: When a device wants to communicate with another device on the same network, it uses ARP to find the MAC address corresponding to the IP address.

Reverse linked list in groups of k nodes

• Iterate through the linked list in groups of k nodes

• Reverse each group of k nodes using iterative or recursive approach

• Update the pointers accordingly to reverse the entire linked list in groups of k

Multiprocessing involves multiple processes running concurrently, while multithreading involves multiple threads within a single process.

• Multiprocessing uses multiple processes to execute tasks simultaneously.

• Multithreading uses multiple threads within a single process to achieve parallelism.

• Multiprocessing is more memory-intensive as each process has its own memory space.

• Multithreading is more lightweight as threads share the same memory space.

• Example: Running multiple insta...read more

C++ constructors can output messages to the console using cout or printf.

• Constructors can be used to initialize member variables and allocate memory.

• Outputting messages in constructors can be useful for debugging and logging.

• Example: class Person { public: Person() { cout << "Person object created."; } };

• Example: class Car { public: Car() { printf("Car object created.\n"); } };