How reader and writer problem was implemented and come up
with effective solution for reader and writer problem in
case we have n readers and 1 writer.

Answer Posted / ashwini

#include<stdio.h>
#include<pthread.h>

pthread_mutex_t m;

void* writer(void*);
void* reader(void*);

FILE *fp;



main()
{
pthread_t tid1,tid2,tid3;
pthread_mutex_init(&m,NULL);
pthread_create(&tid2,NULL,reader,NULL);
pthread_create(&tid1,NULL,writer,NULL);
pthread_create(&tid3,NULL,reader,NULL);

pthread_join(tid2,NULL);
pthread_join(tid1,NULL);
pthread_join(tid3,NULL);
}
void* writer(void *str)
{
pthread_mutex_lock(&m);

fp=fopen("file1.txt","w");
global += 35;
fprintf(fp,"%d",100);
fclose(fp);
pthread_mutex_unlock(&m);
}
void* reader(void *param)
{
int abc;
pthread_mutex_lock(&m);
fp=fopen("file1.txt","r");
fscanf(fp,"%d",&abc);
printf("%d",global);
fclose(fp);
pthread_mutex_unlock(&m);
}

Is This Answer Correct ?    15 Yes 12 No



Post New Answer       View All Answers


Please Help Members By Posting Answers For Below Questions

write a program that reads a series of strings and prints only those strings begging with letter "b"

2865


1+1/2!+1/3!+...+1/n!

2144


What output does this program generate as shown? Why? class A { A() { cout << "A::A()" << endl; } ~A() { cout << "A::~A()" << endl; throw "A::exception"; } }; class B { B() { cout << "B::B()" << endl; throw "B::exception"; } ~B() { cout << "B::~B()"; } }; int main(int, char**) { try { cout << "Entering try...catch block" << endl; A objectA; B objectB; cout << "Exiting try...catch block" << endl; } catch (char* ex) { cout << ex << endl; } return 0; }

786


create a stucture student containing field for roll no,class,year and marks.create 10 student annd store them in a file

2431


write a program to perform generic sort in arrays?

2799






find level of following tree (state, parent) " J,D I,D H,C E,B F,B G,C B,A D,A C,A A,& K,E L,E L,F M,F N,G O,H P,I P,H Q,I R,J S,K U,P T,L

2210


How to Split Strings with Regex in Managed C++ Applications?

3300


3. Program to find the Sum of give series. a. (1)+(1+2)+(1+2+3)+(1+2+3+4)+……………………………….. b. 1/1+1/9+1/25+1/49+……………...

4568


Question 1: Implement a base class Appointment and derived classes Onetime, Daily, Weekly, and Monthly. An appointment has a description (for example, “see the dentist”) and a date and time. Write a virtual function occurs_on(int year, int month, int day) that checks whether the appointment occurs on that date. For example, for a monthly appointment, you must check whether the day of the month matches. Then fill a vector of Appointment* with a mixture of appointments. Have the user enter a date and print out all appointments that happen on that date. *This Should Be Done IN C++

825


Write a C/C++ program that connects to a MySQL server and checks if the InnoDB plug-in is installed on it. If so, your program should print the total number of disk writes by MySQL.

2263


Code for Two Classes for Doing Gzip in Memory?

2986


solve the problem in the programming language C++"if a five digit number is input through the keyboard.Write a program to calculate the sum of its digits(hint: use the modulus operator)

3144


Ask the user to input three positive integers M, N and q. Make the 2 dimensional array of integers with size MxN, where all the elements of I (I = 1,…,M) line will be members of geometrical progression with first element equal to the number of line (I) and denominator q.

3615


We need to write the function to check the password entered is correct or not based on the following conditions.. a) It must have atleast one lower case character and one digit. b)It must not have any Upper case characters and any special characters c) length should be b/w 5-12. d) It should not have any same immediate patterns like abcanan1 : not acceptable coz of an an pattern abc11se: not acceptable, coz of pattern 11 123sd123 : acceptable, as not immediate pattern adfasdsdf : not acceptable, as no digits Aasdfasd12: not acceptable, as have uppercase character

4199


Definition of priority queue was given. We have to implement the priority queue using array of pointers with the priorities given in the range 1..n. The array could be accessed using the variable top. The list corresponding to the array elements contains the items having the priority as the array index. Adding an item would require changing the value of top if it has higher priority than top. Extracting an item would require deleting the first element from the corresponding queue. The following class was given: class PriorityQueue { int *Data[100]; int top; public: void put(int item, int priority); // inserts the item with the given priority. int get(int priority); // extract the element with the given priority. int count(); // returns the total elements in the priority queue. int isEmpty(); // check whether the priority queue is empty or not. }; We had to implement all these class functions.

4629