CS 421 Objectives: Write a program to compare the performance of the Round Robin, non-preemptive Shortest Job First, and SRTF scheduling algorithms. Details: Input: A file of processes and related CPU...

CODE
#include
#include
#include
#include
using namespace std;
class process {
public:
pid_t p_no = 0;
time_t start_AT = 0, AT = 0,
BT_left = 0, BT = 0, temp_BT = 0,
CT = 0, TAT = 0, WT = 0, RT = 0;
int priority = 0;


void set_CT(time_t time)
{
CT = time;
set_TAT();
set_WT();
}

void set_TAT()
{
TAT = CT - start_AT;
}

void set_WT()
{
WT = TAT - BT;
}
void P_set()
{
start_AT = AT;
BT_left = BT;
}
void set_RT(time_t time)
{
RT = time - start_AT;
}

friend bool operator<(const process& a, const process& b)
{
return a.AT > b.AT;
}
};
process pop_index(priority_queue* main_queue, int index)
{
priority_queue rm_index;
int i;
process p;
switch (index) {
case 0:
p = (*main_queue).top();
(*main_queue).pop();
break;
default:
for (i = 0; i < index; i++) {
rm_index.push((*main_queue).top());
(*main_queue).pop();
}
p = (*main_queue).top();
(*main_queue).pop();
while (!(*main_queue).empty()) {
rm_index.push((*main_queue).top());
(*main_queue).pop();
}
(*main_queue) = rm_index;
break;
}
return p;
}
time_t min_BT(priority_queue main_queue, time_t clock)
{
time_t min = 0;
while (!main_queue.empty() && main_queue.top().AT <= clock) {
if (min == 0 || min > main_queue.top().BT_left)
min = main_queue.top().BT_left;
main_queue.pop();
}
return min;
}
int min_BT_index(priority_queue main_queue, time_t limit)
{
int index, i = 0;
time_t min = 0;
while (!main_queue.empty() && main_queue.top().AT <= limit) {
if (min == 0 || main_queue.top().BT_left < min) {
min = main_queue.top().BT_left;
index = i;
}
main_queue.pop();
i++;
}
return index;
}

priority_queue SJF_P_run(priority_queue ready_queue,
queue* gantt)
{
priority_queue completion_queue;
process p;
time_t clock = 0;

while (!ready_queue.empty()) {
while (clock < ready_queue.top().AT) {
p.temp_BT++;
clock++;
}
if (p.temp_BT > 0) {
p.p_no = -1;
p.CT = clock;
(*gantt).push(p);
}
p = pop_index(&ready_queue, min_BT_index(ready_queue, clock));
if (p.AT == p.start_AT)
p.set_RT(clock);
while (p.BT_left > 0 && (ready_queue.empty()
|| clock < ready_queue.top().AT
|| p.BT_left <= min_BT(ready_queue, clock))) {
p.BT_left--;
p.temp_BT++;
clock++;
}
if (p.BT_left == 0) {
p.AT = p.start_AT;
p.set_CT(clock);
(*gantt).push(p);
p.temp_BT = 0;
completion_queue.push(p);
}
else {
p.AT = clock;
p.CT = clock;
(*gantt).push(p);
p.temp_BT = 0;
ready_queue.push(p);
}
}

return completion_queue;
}
priority_queue SJF_NP_run(priority_queue ready_queue,
queue* gantt)
{
priority_queue completion_queue;
process p;
time_t clock = 0;
...