C++ Code Help:

Edit the following codes or code to get the desired output:

First Code:

#include

#include

#include

#define TOTAL_THREADS 4

int count;

pthread_mutex_t the_mutex; // phread mutex variable

void* myFunction(void* arg)

{

int actual_arg = *((int*) arg);

for(unsigned int i = 0; i

// TODO:

// Use a Pthread mutex to control

// access to the critical region.

// Beginning of the critical region

count++;

std::cout

// Random wait - This code is just to ensure that the threads

// show data sharing problems

int max = rand() % 100000;

for (int x = 0; x

// End of random wait code

// End of the critical region

}

pthread_exit(NULL);

}

int main()

{

int rc[TOTAL_THREADS];

pthread_t ids[TOTAL_THREADS];

int args[TOTAL_THREADS];

// TODO: Initialize the pthread mutex here

count = 0;

for(unsigned int i = 0; i

args[i] = i;

rc[i] = pthread_create(&ids[i], NULL, myFunction, (void*) &args[i]);

}

for(unsigned int i = 0; i

pthread_join(ids[i], NULL);

}

std::cout

pthread_exit(NULL);

}

Second Code:

#include

#include

#include

#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

// 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

// Random wait - This code is just to ensure that the threads

// show data sharing problems

int max = rand() % 100000;

for (int x = 0; x

// End of random wait code

// End of the critical region

// TODO:

// Make sure that the other thread gets a turn

//

// HINT: You need one function call

}

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

args[i] = i;

rc[i] = pthread_create(&ids[i], NULL, myFunction, (void*) &args[i]);

}

for(unsigned int i = 0; i

pthread_join(ids[i], NULL);

}

std::cout

pthread_exit(NULL);

}

Output:

Order of threads a can be different just as long as the final count is 40

Thread #0 count 1 Thread #0 count 2 Thread #0 count = 3 Thread #0 count = Thread #0 count . S Thread #0 count 6 Thread #0 count = 7 Thread #0 count 8 Thread #0 count = 9 Thread #0 count 1e Thread #3 count = 11 Thread #3 count = 12 Thread #3 count . 13 Thread #3 count 14 Thread #3 count-15 Thread #3 count 16 Thread #3 count = 17 Thread #3 count 18 Thread #3 count = 19 Thread #3 count 20 Thread #2 count . 21 Thread #1 count 22 Thread #1 count 23 Thread #1 count 24 Thread #1 count = 25 Thread #1 count 26 Thread #1 count = 27 Thread #1 count 28 Thread #1 count . 29 Thread #1 count 30 Thread #1 count = 31 Thread #2 count32 Thread #2 count 33 Thread #2 count 34 Thread #2 count 35 Thread #2 count 36 Thread #2 count . 37 Thread #2 count 38 Thread #2 count-39 Thread #2 count 40 Final count = 48