Làm ơn ai đó giúp mình giải thích các hàm trong bài code c++ này được không ạ?
#include<bits/stdc++.h>
using namespace std;
int processes[100][3], NP, quantum, scheduler[1000],WT[100];
unsigned int timet= 0;
typedef struct el
{
unsigned int p;
struct el * next;
}Q;
Q * qeue = NULL;
void getSystem()
{
int i;
cout << "\nNumber of processes: ";
cin >> NP;
cout << "\nThe Quantum: ";
cin >> quantum;
for(i=0; i<NP; i++ )
{
cout << "\n Arrival Time of p" << i << ": ";
cin >>processes[i][0];
cout << "\n Burst time for p" << i << ": ";
cin >> processes[i][1];
processes[i][2] = processes[i][1];
cout << "\n-----------";
}
}
void printSystem()
{
int i;
cout << "\n\t\tOur System is :";
cout << "\nQuantum: " << quantum;
cout << "\nPi: AT BT RT";
for(i=0; i<NP; i++)
{
cout << "\nP" << i << ": " << processes[i][0] << " " << processes[i][1] << " " << processes[i][2];
}
cout << "\nThe qeue: ";
Q *n;
for(n=qeue; n!=NULL; n=n->next)
{
cout << "P" << n->p;
}
}
unsigned int executionRemained()
{
int i;
unsigned int x = 0;
for(i=0; i<NP; i++)
{
if(processes[i][2] > 0)
{
x = 1;
}
}
return x;
}
void addToQeue(int i)
{
Q *n, *n1;
n = (Q *)malloc(sizeof(Q));
n->next = NULL;
n->p = i;
if(qeue == NULL)
{
qeue = n;
}
else
{
for(n1 = qeue ; n1->next!=NULL; n1=n1->next);
n1 -> next = n;
}
}
void addArrivedProcessesToQeue()
{
int i;
for(i=0; i<NP; i++)
{
if(processes[i][0] == timet)
{
addToQeue(i);
}
}
}
unsigned int getNextProcess()
{
Q *n;
int x;
if(qeue == NULL)
{
return -1;
}
else
{
x = qeue -> p;
n = qeue;
qeue = qeue -> next;
free(n);
return x;
}
}
void schedule()
{
unsigned int np, toRun, q, i;
q = 0;
addArrivedProcessesToQeue();
while(executionRemained())
{
np = getNextProcess();
if(np == -1)
{
/*
here if there is no process in waiting qeue
which mean the process get IDLe state.
here in this program we put -1 in scheduler[time]
which mean that the processor get IDLE in this time.
*/
scheduler[timet] = -1;
timet++;
addArrivedProcessesToQeue();
}
else
{
q = quantum;
if(processes[np][2] < q)
{
q = processes[np][2];
}
for(i = q; i>0; i--)
{
scheduler[timet]=np;
timet++;
processes[np][2]--;
addArrivedProcessesToQeue();
}
if(processes[np][2] > 0)
{
addToQeue(np);
}
}
printSystem();
int x;
}
}
void printScheduling()
{
int i;
cout << "\n\nScheduling: " << endl;
for(i=0; i<timet; i++)
{
cout << "[" << i << "-" << i+1 << "] (P" << scheduler[i] << ") " << endl;
}
cout << "\n\nWaiting Time: " << endl;
for(i=0; i<NP; i++)
{
cout << "\nP" << i << ": " << WT[i];
}
//counting Average Waiting Time...
float AWT = 0.0;
for(i=0; i<NP; i++)
{
AWT = AWT+WT[i];
}
AWT = AWT/NP;
cout << "\n\nAverage Waiting Time: " << AWT;
}
void WatingTime()
{
int i;
unsigned int releaseTime, t;
for(i=0; i<NP; i++)
{
for(t=timet-1; scheduler[t]!= i; t--);
releaseTime = t+1;
WT[i] = releaseTime - processes[i][0] - processes[i][1];
}
}
main()
{
getSystem();
printSystem();
schedule();
WatingTime();
printScheduling();
}
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