C program on shortest-job-first scheduling algorithm?

Answer 1

#include #include #include void main() { char p[10][5],temp[5]; int tot=0,wt[10],pt[10],i,j,n,temp1; float avg=0; clrscr(); printf("enter no of processes:"); scanf("%d",&n); for(i=0;i\n",i+1); scanf("%s",&p[i]); printf("enter process time"); scanf("%d",&pt[i]); } for(i=0;ipt[j]) { temp1=pt[i]; pt[i]=pt[j]; pt[j]=temp1; strcpy(temp,p[i]); strcpy(p[i],p[j]); strcpy(p[j],temp); } } } wt[0]=0; for(i=1;i\t P_time\t w_time\n"); for(i=0;i\t%d\t%d\n",p[i],et[i],wt[i]); printf("total waiting time=%d\n avg waiting time=%f",tot,avg); getch(); }

Answer 2

This is perfectly executing code.

#include<stdio.h>

int n, start;

struct process

{

int id;

int at,st,et,bt,tat,wt,flag,rt,priority;

}p[10],temp,q[10];

void display();

void fcfs();

void sjf();

void sjfpre();

void priority();

void prioritypre();

void main()

{

int i,j,min,u,ch;

printf("\nEnter the total no. of processes:");

scanf("%d",&n);

for(i=0;i<n;i++)

{

printf("\n enter the process id:");

scanf("%d",&q[i].id);

printf("\n enter process arrival time:");

scanf("%d",&q[i].at);

printf("\n enter process burst time:");

scanf("%d",&q[i].bt);

printf("\n enter the priority of the process:");

scanf("%d",&q[i].priority);

q[i].flag=0;

q[i].rt=q[i].bt;

}

do

{

for(i=0;i<n;i++)

{

p[i]=q[i];

}

min=999;

for(i=0;i<n;i++)

{

if(p[i].at<min)

{

min=p[i].at;

u=i;

}

// p[i].rt=p[u].bt;

}

start=p[u].at;

printf("\n1. fcfs");

printf("\n2.sjf");

printf("\n3.sjfpre");

printf("\n4.priority");

printf("\n5.prioritypre");

printf("\n6 exit");

printf("\n enter your choice:");

scanf("%d",&ch);

switch(ch)

{

case 1: fcfs();

break;

case 2: sjf();

break;

case 3: sjfpre();

break;

case 4: priority();

break;

case 5: prioritypre();

break;

// case 6: exit 0;

// break;

}

if(ch!=6)

display();

}while(ch!=6);

}

void display()

{

float turn=0, wait=0;

int i;

printf("\nprocess\tarrivaltime\tbursttime\tstarttime\tendtime\tpriority\twaitingtime\tturnaroundtime");

for(i=0;i<n;i++)

{

p[i].tat=p[i].et-p[i].at;

p[i].wt=p[i].tat-p[i].bt;

wait=wait + p[i].wt;

turn=turn + p[i].tat;

printf("\n%d\t%d\t%d\t%d\t%d\t%d\t%d\t%d\n",p[i].id,p[i].at,p[i].bt,p[i].st,p[i].et,p[i].priority,p[i].wt,p[i].tat);

}

wait=wait/n;

turn=turn/n;

printf("\nAverage waiting time is: %f",wait);

printf("\nAverage turnaround time is: %f",turn);

}

void fcfs()

{

int i,j;

for(i=0;i<n;i++)

for(j=i+1;j<n;j++)

{

if(p[i].at>p[j].at)

{

temp=p[i];

p[i]=p[j];

p[j]=temp;

}

}

start=p[0].at;

for(i=0;i<n;i++)

{

if(start<p[i].at)

start=p[i].at;

p[i].st=start;

p[i].et=start + p[i].bt;

start=p[i].et;

}

}

void sjf()

{

int i,j,min,u;

for(j=0;j<n;j++)

{

min=999;

for(i=0;i<n;i++)

if(p[i].at<=start && p[i].bt < min && p[i].flag==0)

{

min=p[i].bt;

u=i;

}

if(min==999)

{

for(i=0;i<n;i++)

if(p[i].at<min && p[i].flag==0)

{

min=p[i].at;

u=i;

}

start=p[u].at;

}

p[u].st=start;

p[u].et=start + p[u].bt;

p[u].flag=1;

start=p[u].et;

}

}

void sjfpre()

{

int i,j=0,min,u;

while(j<n)

{

min=999;

for(i=0;i<n;i++)

if(p[i].at<=start && p[i].rt<min && p[i].flag==0)

{

min=p[i].rt;

u=i;

}

if(min==999)

{

for(i=0;i<n;i++)

if(p[i].at<min && p[i].flag==0)

{

min=p[i].at;

u=i;

}

start=p[u].at;

}

if(p[u].bt==p[i].rt)

p[u].st=start;

p[u].rt=p[u].rt-1;

start=start+1;

if(p[u].rt==0)

{

p[u].et=start;

p[u].flag=1;

j++;

}

}

}

void priority()

{

int i,j,min,u;

for(j=0;j<n;j++)

{

min=999;

for(i=0;i<n;i++)

if(p[i].at<=start && p[i].priority < min && p[i].flag==0)

{

min=p[i].priority;

u=i;

}

if(min==999)

{

for(i=0;i<n;i++)

if(p[i].at<min && p[i].flag==0)

{

min=p[i].at;

u=i;

}

start=p[u].at;

}

p[u].st=start;

p[u].et=start + p[u].bt;

p[u].flag=1;

start=p[u].et;

}

}

void prioritypre()

{

int i,j=0,min,u;

while(j<n)

{

min=999;

for(i=0;i<n;i++)

if(p[i].at<=start && p[i].priority<min && p[i].flag==0)

{

min=p[i].priority;

u=i;

}

if(min==999)

{

for(i=0;i<n;i++)

if(p[i].at<min && p[i].flag==0)

{

min=p[i].at;

u=i;

}

start=p[u].at;

}

if(p[u].bt==p[i].rt)

p[u].st=start;

p[u].rt=p[u].rt-1;

start=start+1;

if(p[u].rt==0)

{

p[u].et=start;

p[u].flag=1;

j++;

}

}

}

code written by : Fabianski Benjamin