Question

In an office there is a unisex bathroom with n toilets. The bathroom is open to both men and women, but it cannot be used by men and women at the same time. Develop a concurrent program that simulates the above scenario using semaphores. Your solution should be deadlock free, but it does not have to be starvation free. Note that your program has to implement two functions arriveAtTheBathroom(type) and leaveTheBathroom(type), where type is either MAN or WOMAN
#include "BathroomProblemSolverInterface.cpp"
#include

class MyBathroomProblemSolver : public BathroomProblemSolverInterface
{
int n;//Number of toilets
public:
MyBathroomProblemSolver(int n)
{
this->n = n;
}
void arriveAtTheBathroom(gender type) override
{
throw std::runtime_error("Not Implemented");
/******************************************
*
*
* Your Code goes here
*
*
*
* ***************************************/
}

void leaveTheBathroom(gender type) override
{
throw std::runtime_error("Not Implemented");
/******************************************
*
*
* Your Code goes here
*
*
*
* ***************************************/
}
};

Answer 1

Answer:

Check the explanation

Explanation:

#include <stdio.h>

#include <stdlib.h>

#include <pthread.h>

#include <semaphore.h>

int mcount,wcount;

sem_t x,y,z,wsem,msem,cap;

void delay(void)

{

int i;

int delaytime;

delaytime = random();

for (i = 0; i<delaytime; i++);

}

void *woman(void *param)

{

sem_wait(&z);

sem_wait(&wsem);

sem_wait(&y);

wcount++;

if(wcount==1)

{ sem_wait(&msem); }

sem_post(&y);

sem_post(&wsem);

sem_post(&z);

sem_wait(&cap);

printf("woman in!\n");

delay();

printf("\twoman out!\n");

sem_post(&cap);  

sem_wait(&y);

wcount--;

if(wcount==0)

{ sem_post(&msem); }

sem_post(&y);

}

void *man(void *param)

{  

sem_wait(&z);

sem_wait(&msem);

sem_wait(&x);

mcount++;

if(mcount==1)

{ sem_wait(&wsem); }

sem_post(&x);

sem_post(&msem);

sem_post(&z);

sem_wait(&cap);

printf("\t\tman in!\n");

delay();

printf("\t\t\tman out!\n");

sem_post(&cap);

sem_wait(&x);

mcount--;

if(mcount==0)

{sem_post(&wsem);}

sem_post(&x);

}

int main(void)

{

int i;

srandom(60);

mcount = 0;

wcount = 0;

sem_init(&x,0,1); // for sem_init, initial value is 3rd argument

sem_init(&y,0,1);

sem_init(&z,0,1);

sem_init(&wsem,0,1);

sem_init(&msem,0,1);

sem_init(&cap,0,4); // eg. cap initialized to 4

pthread_t *tid;

tid = malloc(80*sizeof(pthread_t));

// You can use your cobegin statement here, instead of pthread_create()  

// I have forgone the use of pthread barriers although I suppose they would nicely imitate the functionality of cobegin.

// This is merely to retain simplicity.

for(i=0;i<10;i++)

{

pthread_create(&tid[i],NULL,woman,NULL);

}

for(i=10;i<20;i++)

{  

pthread_create(&tid[i],NULL,man,NULL);

}

for(i=0;i<20;i++)

{  

pthread_join(tid[i],NULL);

}

return(0);

}