Write a program in C/C++ to implement reader- writer problem






Write a program in C/C++ to implement reader- writer problem..

Answer / pranaybaldi

Readers-Writers Problem:
The readers-writers problem is a classic synchronization
problem in which two
distinct classes of threads exist, reader and writer.
Multiple reader threads
can be present in the Database simultaneously. However, the
writer threads must
have exclusive access. That is, no other writer thread, nor
any reader thread,
may be present in the Database while a given writer thread
is present. Note:
the reader/writer thread must call startRead()/startWrite()
to enter the
Database and it must call endRead()/endWrite() to exit the
Database.
class Database extends Object {
private int numReaders = 0;
private int numWriters = 0;
private ConditionVariable OKtoRead = new ConditionVariable
();
private ConditionVariable OKtoWrite = new ConditionVariable
();
public synchronized void startRead() {
while (numWriters > 0)
wait(OKtoRead);
numReaders++;
}
public synchronized void endRead() {
numReaders--;
notify(OKtoWrite);
}
public synchronized void startWrite() {
while (numReaders > 0 || numWriters > 0)
wait(OKtoWrite);
numWriters++;
}
public synchronized void endWrite() {
numWriters--;
notify(OKtoWrite);
notifyAll(OKtoRead);
}
}
class Reader extends Object implements Runnable {
private Monitor m = null;
public Reader(Monitor m) {
this.m = m;
new Thread(this).start();
}
public void run() {
//do something;
m.startRead();
//do some reading…
m.endRead();
// do something else for a long time;
}
}
class Writer extends Object implements Runnable {
private Monitor m = null;
public Writer(Monitor m) {
this.m = m;
new Thread(this).start();
}
public void run() {
//do something;
m.startWrite();
//do some writing…
m.endWrite();
// do something else for a long time;
}
}
- 2 -
wait(ConditionVariable cond) {
put the calling thread on the “wait set” of cond;
release lock;
Thread.currentThread.suspend();
acquire lock;
}
notify(ConditionVariable cond){
choose t from wait set of cond;
t.resume();
}
notifyAll(ConditionVariable cond){
forall t in wait set of cond;
t.resume()
}
For the following scenarios, we assume that only one reader
thread and one writer
thread are running on the processor.

Is This Answer Correct ?    15 Yes 41 No

Post New Answer




More STL Interview Questions

c# support late binding or early binding.

6 Answers  


sir please send me bpcl previous question papers

0 Answers   BPCL Bharat Petroleum,


When did c++ add stl?

0 Answers  


Q1. A. What is unary operator? List out the different operators involved in the unary operator. B. What is an adjust field format flag? Q2. A. Distinguish between a # include and #define. B. Can a list of string be stored within a two dimensional array? Q3. A.Explain how a pointer to function can be declared in C++? B.List the merits and demerits of declaring a nested class in C++? Q4. A. What are the syntactic rules to be avoid ambiguity in multiple inheritence? B. Explain the operation of overloading of an assignment operator. Q5. A. Explain how the virtual base class is different from the conventional base classes of the opps. B. Explain how an exception handler is defined and invoked in a Program. Q6. A. What is a binary file? List the merits and demerits of the binary file usagein C++. B. Write short notes on Text Manipulation Routines. C. Write bites in Turbo c++ Header (“Include”) Files.

0 Answers   Infosys, GE, Microsoft, NIM,


a program using one dimensional array that searches a number if it is found on the list of given input numbers given by the user and locate its exact location in the list.

0 Answers  






Write a program in C/C++ to implement reader- writer problem

1 Answers   Wipro,


Name the different types of stl containers.

0 Answers  


WHAT IS FIBONACCI SERIES?

4 Answers   Stewart,


what are you now programming Languages C+

1 Answers   HCL,


In what scenario does the Logical file and Physical file being used?

0 Answers   informatics,


What does stl mean in slang?

0 Answers  


In what cases using of a 'template' is a better approach then using of a 'base class'?

6 Answers   Wipro, Lucent, Mind Tree,






Categories