Can someone look at this code and tell me what it does and add comments within the code to explain methods

#include

#include

#include

#include

using namespace std;

#define MIN_PID 300

#define MAX_PID 5000

int threadVar = 0;

pthread_mutex_t mutex;

struct pid_tab

{

int pid;

bool bitmap;

}pidArr[4700];

int allocate_map(void) //allocates bitmap values to the data structure

{

int i,j;

for(i = MIN_PID, j =0; i <= MAX_PID; i++, j++)

{

pidArr[j].pid = i;

pidArr[j].bitmap = 0;

}

if(i == MAX_PID && j == 4700)

return 1;

else

return -1;

}

int allocate_pid(void) //allocates a pid to the new process

{

for(int i = MIN_PID, j =0; i <= MAX_PID; i++, j++)

{

if(pidArr[j].bitmap == 0)

{

pidArr[j].pid = i;

pidArr[j].bitmap = 1;

return i;

break;

}

}

return -1;

}

void release_pid(int pid) //releases pid

{

for(int i = 0; i <= 4700; i++)

{

if(pidArr[i].pid == pid)

{

pidArr[i].bitmap = 0;

}

}

}