86 lines
2.4 KiB
C++
86 lines
2.4 KiB
C++
|
#include <stdio.h>
|
||
|
|
#include <iostream>
|
||
|
|
|
||
|
|
using namespace std;
|
||
|
|
|
||
|
|
struct process
|
||
|
|
{
|
||
|
|
int pid; // Process ID
|
||
|
|
int burst_time; // CPU Burst Time
|
||
|
|
int working_time; // Time this process executed, if working_time==burst_time, process is complete
|
||
|
|
int t_round; // turn around time, time needed for the process to complete
|
||
|
|
int arrivalTime; // time for a process to arrive to queue, which is zero in this case
|
||
|
|
int remainTime; // time remaining for a process to complete execution
|
||
|
|
};
|
||
|
|
|
||
|
|
main()
|
||
|
|
{
|
||
|
|
int numProcesses;
|
||
|
|
cout << "Enter the number of processes: ";
|
||
|
|
cin >> numProcesses;
|
||
|
|
struct process pr[numProcesses];
|
||
|
|
|
||
|
|
int i, totalExecutionTime = 0, timeQuantum, flag = 0, n;
|
||
|
|
float totalWaitingTime = 0;
|
||
|
|
|
||
|
|
for (i = 0; i < numProcesses; i++)
|
||
|
|
{
|
||
|
|
cout << "\nEnter PID for process " << i + 1 << " (ms): ";
|
||
|
|
cin >> pr[i].pid;
|
||
|
|
|
||
|
|
cout << "\nEnter Burst Time for process " << i + 1 << " (ms): ";
|
||
|
|
cin >> pr[i].burst_time;
|
||
|
|
}
|
||
|
|
|
||
|
|
// arrival time is zero
|
||
|
|
for (int i = 0; i < numProcesses; i++)
|
||
|
|
{
|
||
|
|
pr[i].arrivalTime = 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
printf("\nEnter Time Quantum: ");
|
||
|
|
scanf("%d", &timeQuantum);
|
||
|
|
|
||
|
|
printf("\n");
|
||
|
|
for (i = 0; numProcesses != 0;)
|
||
|
|
{
|
||
|
|
/**
|
||
|
|
* this below condition check the remain time for any process is less than or equal with the time quantum
|
||
|
|
* or not and also check the remain time is greater than 0 or not. if both condition are true that means
|
||
|
|
* the process can execute fully at one time.
|
||
|
|
*/
|
||
|
|
if (pr[i].remainTime <= timeQuantum && pr[i].remainTime > 0)
|
||
|
|
{
|
||
|
|
totalExecutionTime += pr[i].remainTime;
|
||
|
|
pr[i].remainTime = 0;
|
||
|
|
flag = 1;
|
||
|
|
}
|
||
|
|
|
||
|
|
else if (pr[i].remainTime > 0)
|
||
|
|
{
|
||
|
|
pr[i].remainTime -= timeQuantum;
|
||
|
|
totalExecutionTime += timeQuantum;
|
||
|
|
}
|
||
|
|
|
||
|
|
if (flag == 1 && pr[i].remainTime == 0)
|
||
|
|
{
|
||
|
|
printf("P[%d] | waiting Time : %d\n", i + 1, totalExecutionTime - pr[i].burst_time);
|
||
|
|
totalWaitingTime += totalExecutionTime - pr[i].burst_time;
|
||
|
|
flag = 0;
|
||
|
|
numProcesses--;
|
||
|
|
}
|
||
|
|
|
||
|
|
if (i == n - 1)
|
||
|
|
i = 0;
|
||
|
|
else if (pr[i + 1].arrivalTime <= totalExecutionTime)
|
||
|
|
{
|
||
|
|
i++;
|
||
|
|
}
|
||
|
|
else
|
||
|
|
i = 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
totalWaitingTime = (float)totalWaitingTime / n;
|
||
|
|
printf("\nThe Average Waiting Time : %.2f \n", totalWaitingTime);
|
||
|
|
}
|