Skip to content

Instantly share code, notes, and snippets.

@hatim-the-dark-knight

hatim-the-dark-knight/fcfs.c

Last active April 27, 2022 03:22
Show Gist options
  • Save hatim-the-dark-knight/1e4b21dbe28b29f45b4c35035e514469 to your computer and use it in GitHub Desktop.
Save hatim-the-dark-knight/1e4b21dbe28b29f45b4c35035e514469 to your computer and use it in GitHub Desktop.
Download ZIP
Raw
fcfs.c
// FCFS SCHEDULING
#include<stdio.h>
struct process {
int pid, atime, btime, ctime, tatime, wtime;
};
int main () {
printf ("FCFS SCHEDULING\n");
int n, ttatime = 0, twtime = 0;
printf ("Enter the no. of processes -> ");
scanf ("%d", &n);
struct process p[n], temp;
printf ("\nP\tAT\tBT\n");
for (int i = 0; i < n; i++) {
p[i].pid = i+1;
printf ("P%d\t", p[i].pid);
scanf ("%d\t%d", &p[i].atime, &p[i].btime);
p[i].ctime = 0;
p[i].tatime = 0;
p[i].wtime = 0;
}
for (int i = 0; i < n-1; i++) {
for (int j = 0; j < n-i-1; j++) {
if (p[j].atime > p[j+1].atime) {
temp = p[j];
p[j] = p[j+1];
p[j+1] = temp;
}
}
}
for (int i = 0; i < n; i++) {
if (i == 0)
p[0].ctime = p[0].atime + p[0].btime;
else if (p[i].atime < p[i-1].ctime)
p[i].ctime = p[i-1].ctime + p[i].btime;
else
p[i].ctime = p[i].atime + p[i].btime;
p[i].tatime = p[i].ctime - p[i].atime;
p[i].wtime = p[i].tatime -p[i].btime;
ttatime += p[i].tatime;
twtime += p[i].wtime;
}
printf ("\nP\tAT\tBT\tCT\tTAT\tWT\n");
for (int i = 0; i < n; i++) {
printf ("\nP%d\t%d\t%d\t%d\t%d\t%d", p[i].pid, p[i].atime, p[i].btime, p[i].ctime, p[i].tatime, p[i].wtime);
}
printf ("\n\nAverage TAT -> %f", (float) ttatime/n);
printf ("\nAverage WT -> %f\n\n", (float) twtime/n);
}
Raw
pris.c
// PRIORITY CPU SCHEDULING
#include<stdio.h>
struct pris {
int pid, pri, atime, btime, ctime, wtime, tatime;
short check;
};
void main () {
int i, j, k, n, t, twtime = 0, ttatime;
printf ("PRIORITY SCHEDULING\n\nEnter the no. of processes -> ");
scanf ("%d", &n);
struct pris p[n];
int q[n];
printf ("\nInput Pri, AT and BT ->\n\n\tPri\tA.T\tB.T\n");
for (i = 0; i < n; i++) {
p[i].pid = i; p[i].check = 0; p[i].ctime = 0; p[i].wtime = 0; p[i].tatime = 0; q[i] = -1;
printf ("P%d\t", p[i].pid);
scanf ("%d %d %d", &p[i].pri, &p[i].atime, &p[i].btime);
}
t = 0; j = 0; k = 0;
while (j != n) {
printf ("\nt updated to %d ", t);
for (i = 0; i < n; i++) {
if (t >= p[i].atime && p[i].check != 1) {
q[j] = i;
p[i].check = 1;
printf (" P%d ", q[j]);
j++;
}
}
printf ("arrived! ");
int temp;
for (i = k; i < j; i++) {
for (int l = i+1; l < j; l++) {
if (p[q[i]].pri > p[q[l]].pri) {
temp = q[i];
q[i] = q[l];
q[l] = temp;
}
else if (p[q[i]].pri == p[q[l]].pri) {
if (p[q[i]].atime > p[q[l]].atime) {
temp = q[i];
q[i] = q[l];
q[l] = temp;
}
}
}
}
t += p[q[k]].btime;
p[q[k]].ctime = t;
p[q[k]].tatime = p[q[k]].ctime - p[q[k]].atime;
p[q[k]].wtime = p[q[k]].tatime - p[q[k]].btime;
twtime += p[q[k]].wtime;
ttatime += p[q[k]].tatime;
printf ("\nP%d executed!", p[q[k]].pid);
k++;
}
for (i = k; i < n; i++) {
printf ("\nt updated to %d ", t);
t += p[q[i]].btime;
p[q[i]].ctime = t;
p[q[i]].tatime = p[q[i]].ctime - p[q[i]].atime;
p[q[i]].wtime = p[q[i]].tatime - p[q[i]].btime;
twtime += p[q[i]].wtime;
ttatime += p[q[i]].tatime;
printf ("\nP%d executed!", p[q[i]].pid);
}
printf ("\n\n\tPri\tA.T\tB.T\tC.T\tT.A.T\tW.T");
for (i = 0; i < n; i++)
printf ("\nP%d\t%d\t%d\t%d\t%d\t%d\t%d", p[q[i]].pid, p[q[i]].pri, p[q[i]].atime, p[q[i]].btime, p[q[i]].ctime, p[q[i]].tatime, p[q[i]].wtime);
printf ("\n\n");
}
Raw
rrs.c
//Round Robin CPU SCHEDULING
#include<stdio.h>
#include<stdlib.h>
struct rrs {
int pid, atime, btime, tempb, ctime, tatime, wtime;
short isTraversed;
};
void main () {
int i, j, k, n, count = 0, qt, curr_time = 0, arriv = 0, leucpid;
float ttatime = 0, twtime = 0;
printf ("\nRRS CPU SCHEDULING\n\nEnter the no. of processes -> ");
scanf ("%d", &n);
struct rrs p[n];
// dynamic allocation for ready queue
int *q;
q = (int *)malloc (sizeof (int));
printf ("\nEnter the values -> \n");
printf ("P[pid]\tAT\tBT\n");
for (i = 0; i < n; i++) {
p[i].isTraversed = 0;
p[i].pid = i;
printf ("P[%d]\t", p[i].pid);
scanf ("%d %d", &p[i].atime, &p[i].btime);
p[i].tempb = p[i].btime; // burstTime left after preemption stored in p[i].tempb
}
printf ("\nEnter the time quantum -> ");
scanf ("%d", &qt);
j = 0; // ready queue index
k = 0; // completed process index in ready queue
leucpid = -1; // stores id of last executed uncomplete process
printf ("\nP\tAT\tBT\tCT\tTAT\tWT");
while (count != n) {
if (arriv < n)
for (i = 0; i < n; i++)
if (p[i].isTraversed == 0) // checks whether a process is traversed once to avoid repetition of processes in the ready queue
if (curr_time >= p[i].atime) {
q[j] = i;
p[q[j]].isTraversed = 1;
arriv++;
j++;
}
if (leucpid != -1) { // for storing id of the preempted process
q[j] = leucpid;
j++;
}
if (p[q[k]].tempb <= qt) {
curr_time += p[q[k]].tempb;
p[q[k]].tempb = 0;
p[q[k]].ctime = curr_time;
p[q[k]].tatime = p[q[k]].ctime - p[q[k]].atime;
p[q[k]].wtime = p[q[k]].tatime - p[q[k]].btime;
ttatime += p[q[k]].tatime;
twtime += p[q[k]].wtime;
printf ("\nP%d\t%d\t%d\t%d\t%d\t%d", p[q[k]].pid, p[q[k]].atime, p[q[k]].btime, p[q[k]].ctime, p[q[k]].tatime, p[q[k]].wtime);
leucpid = -1;
k++;
count++;
}
else if (p[q[k]].tempb > qt) {
curr_time += qt;
p[q[k]].tempb -= qt;
leucpid = p[q[k]].pid;
k++;
}
}
printf ("\n\nAverage Turnaround Time: %f", ttatime/n);
printf ("\nAverage Waiting Time: %f\n\n", twtime/n);
}
Raw
sjf.c
// SJF CPU SCHEDULING
#include<stdio.h>
struct pris {
int pid, atime, btime, ctime, wtime, tatime;
short check;
};
void main () {
int i, j, k, n, t, twtime = 0, ttatime;
printf ("SJF SCHEDULING\n\nEnter the no. of processes -> ");
scanf ("%d", &n);
struct pris p[n];
int q[n];
printf ("\nInput AT and BT ->\n\n\tA.T\tB.T\n");
for (i = 0; i < n; i++) {
p[i].pid = i; p[i].check = 0; p[i].ctime = 0; p[i].wtime = 0; p[i].tatime = 0; q[i] = -1;
printf ("P%d\t", p[i].pid);
scanf ("%d %d", &p[i].atime, &p[i].btime);
}
t = 0; j = 0; k = 0;
while (j != n) {
printf ("\nt updated to %d ", t);
for (i = 0; i < n; i++) {
if (t >= p[i].atime && p[i].check != 1) {
q[j] = i;
p[i].check = 1;
printf (" P%d ", q[j]);
j++;
}
}
printf ("arrived! ");
int temp;
for (i = k; i < j; i++) {
for (int l = i+1; l < j; l++) {
if (p[q[i]].btime > p[q[l]].btime) {
temp = q[i];
q[i] = q[l];
q[l] = temp;
}
else if (p[q[i]].btime == p[q[l]].btime) {
if (p[q[i]].atime > p[q[l]].atime) {
temp = q[i];
q[i] = q[l];
q[l] = temp;
}
}
}
}
t += p[q[k]].btime;
p[q[k]].ctime = t;
p[q[k]].tatime = p[q[k]].ctime - p[q[k]].atime;
p[q[k]].wtime = p[q[k]].tatime - p[q[k]].btime;
twtime += p[q[k]].wtime;
ttatime += p[q[k]].tatime;
printf ("\nP%d executed!", p[q[k]].pid);
k++;
}
for (i = k; i < n; i++) {
printf ("\nt updated to %d ", t);
t += p[q[i]].btime;
p[q[i]].ctime = t;
p[q[i]].tatime = p[q[i]].ctime - p[q[i]].atime;
p[q[i]].wtime = p[q[i]].tatime - p[q[i]].btime;
twtime += p[q[i]].wtime;
ttatime += p[q[i]].tatime;
printf ("\nP%d executed!", p[q[i]].pid);
}
printf ("\n\n\tA.T\tB.T\tC.T\tT.A.T\tW.T\n");
for (i = 0; i < n; i++)
printf ("P%d\t%d\t%d\t%d\t%d\t%d\n", p[q[i]].pid, p[q[i]].atime, p[q[i]].btime, p[q[i]].ctime, p[q[i]].tatime, p[q[i]].wtime);
printf("\nAverage turn around time: %f\n", (float)ttatime/n);
printf("Average waiting time: %f\n\n", (float)twtime/n);
}
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment