1. What is the difference between TCP and UDP ?

TCP and UDP are both transport-level protocols. TCP is designed to provide reliable communication across a variety of reliable and unreliable networks and internets.

UDP provides a connectionless service for application-level procedures. Thus, UDP is basically an unreliable service; delivery and duplicate protection are not guareented.

2. Name of seven layers in Open System Interconnection model.

They are Application, Presentation, Session, Transport, Network, Data link, and Physical.

3. What does a socket consists of ?

The combination of an IP address and a port number is called a socket.

4. What is the null pointer in C++ ?

The null pointer is a special C++ pointer value that can be used for any pointer that doesn’t pointer anywhere. It can be written as the constant NULL form stlib.h

5. What is the time complexity of matrix multiplication ?

void Mult_Matrix(matrix A, matrix B, matrix C)
{
int i, j, k;
for ( i = 1; i < N; i++)
for ( j = 1; j < N; j++ )
{
C[i][j] = 0;
for ( k = 0; k < N; k++ )
C[i][j] = A[i][j]*B[k][j];
}
retrun;
}

The time comlexity of matrix mulitiplication is O(N^3)

6. How does the race condition occur ?

It occurs when two or more processes are reading or writing some shared data and the final result depends on who runs precisely when.

7. Name the seven layers of the OSI Model and describe them briefly.

Physical Layer - covers the physical interface between devices and the rules by which bits are passed from one to another.

Data Link Layer - attempts o make the physical link reliable and provides the means to activate, maintain, and deactivate the link.

Network Layer - provides for the transfer of information between end systems across some sort communications network.

Transport Layer - provides a mechanism for the exchange of data between end system.

Session Layer - provides the mechanism for controlling the dialogue between applications in end systems.

Presentation Layer - defines the format of the data to be exchanged between applications and offers application programs a set of data transformation services.

Application Layer - provides a means for application programs to access the OSI environment.

8. What is the difference between an abstract class and an interface ?

An abstract class may have fields and some implemented methods.

An interface has no implementation; only constants and method declarations.

9. What is multiprogramming ?

Multiprogramming is a rapid switching of the CPU back and forth between processes.

10. What is the goal of the shortest distance algorithm ?

The goal is to completely fill the distance array so that for each vertex v, the value of distance[v] is the weight of the shortest path from start to v.