C+++ #include #include #include #define TOTAL_THREADS 4 int count; pthread_mutex_t the_mutex; // phread mutex variable - initialize here if using the initializer macro void* myFunction(void* arg) { int actual_arg = *((int*) arg); for(unsigned int i = 0; i < 10; ++i) { // TODO: // Use a Pthread mutex to control // access to the critical region. // Beginning of the critical region count++; std::cout << "Thread #" << actual_arg << " count = " << count << std::endl; // End of the critical region // TODO: // Relinquish access to the Pthread mutex // since critical region is complete. // Random wait - This code is just to ensure that the threads // show data sharing problems int max = rand() % 100000; for (int x = 0; x < max; x++); // End of random wait code } pthread_exit(NULL); } int main() { int rc[TOTAL_THREADS]; pthread_t ids[TOTAL_THREADS]; int args[TOTAL_THREADS]; // TODO: Initialize the pthread mutex here if using the initialization function. count = 0; for(unsigned int i = 0; i < TOTAL_THREADS; ++i) { args[i] = i; rc[i] = pthread_create(&ids[i], NULL, myFunction, (void*) &args[i]); } for(unsigned int i = 0; i < TOTAL_THREADS; ++i) { pthread_join(ids[i], NULL); } std::cout << "Final count = " << count << std::endl; pthread_exit(NULL); }

C+++

#include <iostream>
#include <pthread.h>
#include <stdlib.h>

#define TOTAL_THREADS 4

int count;
pthread_mutex_t the_mutex; // phread mutex variable - initialize here if using the initializer macro

void* myFunction(void* arg)
{
int actual_arg = *((int*) arg);

for(unsigned int i = 0; i < 10; ++i) {

// TODO:
// Use a Pthread mutex to control
// access to the critical region.

// Beginning of the critical region

count++;
std::cout << "Thread #" << actual_arg << " count = " << count << std::endl;

// End of the critical region

// TODO:
// Relinquish access to the Pthread mutex
// since critical region is complete.

// Random wait - This code is just to ensure that the threads
// show data sharing problems
int max = rand() % 100000;

for (int x = 0; x < max; x++);

// End of random wait code



}

pthread_exit(NULL);
}

int main()
{
int rc[TOTAL_THREADS];
pthread_t ids[TOTAL_THREADS];
int args[TOTAL_THREADS];


// TODO: Initialize the pthread mutex here if using the initialization function.


count = 0;
for(unsigned int i = 0; i < TOTAL_THREADS; ++i) {
args[i] = i;
rc[i] = pthread_create(&ids[i], NULL, myFunction, (void*) &args[i]);
}

for(unsigned int i = 0; i < TOTAL_THREADS; ++i) {
pthread_join(ids[i], NULL);
}

std::cout << "Final count = " << count << std::endl;
pthread_exit(NULL);
}

---------------------------

#include <iostream>
#include <pthread.h>
#include <stdlib.h>

#define TOTAL_THREADS 2

int count;
int turn; // Shared variable, indicates
// whose turn it is to execute

bool interested[TOTAL_THREADS]; // Shared variable, indicates
// processes interested in executing

// The thread_id will be either 0 or 1
void enter_region(int thread_id)
{
int other; // ID of the other thread

other = 1 - thread_id; // The oposite of thread_id


// TODO: Add the code to indicate the
// thread's interest in executing.


// TODO: Indicate the thread's turn to execute next


// TODO: Busy wait until it is the thread's turn to execute

}

void leave_region(int thread_id)
{
// TODO: Add the code to set the flag
// indicating that the thread has
// exited the critical region.

}

void* myFunction(void* arg)
{
int thread_id = *((int*) arg);

for(unsigned int i = 0; i < 10; ++i) {

// TODO:
// Make sure that the thread waits for its turn
// before it enters the critical region.
//
// HINT: You need one function call


// Beginning of the critical region

count++;
std::cout << "Thread #" << thread_id << " count = " << count << std::endl;

// End of the critical region


// TODO:
// Make sure that the other thread gets a turn
//
// HINT: You need one function call

// Random wait - This code is just to ensure that the threads
// show data sharing problems
int max = rand() % 1000000;

for (int x = 0; x < max; x++);

// End of random wait code
}

pthread_exit(NULL);
}

// HINT: It is not necessary to make any changes in main()
int main()
{
int rc[TOTAL_THREADS];
pthread_t ids[TOTAL_THREADS];
int args[TOTAL_THREADS];

count = 0;
for(unsigned int i = 0; i < TOTAL_THREADS; ++i) {
args[i] = i;
rc[i] = pthread_create(&ids[i], NULL, myFunction, (void*) &args[i]);
}

for(unsigned int i = 0; i < TOTAL_THREADS; ++i) {
pthread_join(ids[i], NULL);
}

std::cout << "Final count = " << count << std::endl;
pthread_exit(NULL);
}