CPU Schedueling programs

        Fcfs program

        #include<stdio.h>
#include<conio.h>
main()
{

int bt[20], wt[20], tat[20], i, n; float wtavg, tatavg;

printf("\nEnter the number of processes -- "); scanf("%d", &n);
for(i=0;i<n;i++)
{

printf("\nEnter Burst Time for Process %d -- ", i); scanf("%d", &bt[i]);

}

wt[0] = wtavg = 0; tat[0] = tatavg = bt[0]; for(i=1;i<n;i++)

{

wt[i] = wt[i-1] +bt[i-1]; tat[i] = tat[i-1] +bt[i]; wtavg = wtavg + wt[i]; tatavg = tatavg + tat[i];

}
printf("\t PROCESS \tBURST TIME \t WAITING TIME\t TURNAROUND TIME\n");
for(i=0;i<n;i++)

printf("\n\t P%d \t\t %d \t\t %d \t\t %d", i, bt[i], wt[i], tat[i]); printf("\nAverage Waiting Time -- %f", wtavg/n);

printf("\nAverage Turnaround Time -- %f", tatavg/n); getch();
}

Output

SJF program

#include<stdio.h>

#include<conio.h>
main()
{

int p[20], bt[20], wt[20], tat[20], i, k, n, temp; float wtavg, tatavg;

printf("\nEnter the number of processes -- "); scanf("%d", &n);

for(i=0;i<n;i++)
{
p[i]=i;

printf("Enter Burst Time for Process %d -- ", i); scanf("%d", &bt[i]);

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

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

if(bt[i]>bt[k])
{

temp=bt[i];

bt[i]=bt[k];

bt[k]=temp;

temp=p[i];

p[i]=p[k];

p[k]=temp;
}

wt[0] = wtavg = 0; tat[0] = tatavg = bt[0]; for(i=1;i<n;i++)

{

wt[i] = wt[i-1] +bt[i-1]; tat[i] = tat[i-1] +bt[i]; wtavg = wtavg + wt[i]; tatavg = tatavg + tat[i];

}

printf("\n\t PROCESS \tBURST TIME \t WAITING TIME\t TURNAROUND TIME\n"); for(i=0;i<n;i++)

printf("\n\t P%d \t\t %d \t\t %d \t\t %d", p[i], bt[i], wt[i], tat[i]); printf("\nAverage Waiting Time -- %f", wtavg/n);

printf("\nAverage Turnaround Time -- %f", tatavg/n); getch();
}

Output

Round Robin Program

#include<stdio.h>

main()
{

int i,j,n,bu[10],wa[10],tat[10],t,ct[10],max; float awt=0,att=0,temp=0;


printf("Enter the no of processes -- "); scanf("%d",&n);

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

{

printf("\nEnter Burst Time for process %d -- ", i+1); scanf("%d",&bu[i]);

ct[i]=bu[i];

}

printf("\nEnter the size of time slice -- "); scanf("%d",&t);

max=bu[0];

for(i=1;i<n;i++)
if(max<bu[i])

max=bu[i];

for(j=0;j<(max/t)+1;j++)

for(i=0;i<n;i++)
if(bu[i]!=0)

if(bu[i]<=t)

{

tat[i]=temp+bu[i];
temp=temp+bu[i];

bu[i]=0;

}
else

{

bu[i]=bu[i]-t; temp=temp+t;
}

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

{

wa[i]=tat[i]-ct[i]; att+=tat[i];


awt+=wa[i];
}
printf("\nThe Average Turnaround time is -- %f",att/n);
printf("\nThe Average Waiting time is -- %f ",awt/n);
printf("\n\tPROCESS\t BURST TIME \t WAITING TIME\tTURNAROUND TIME\n");
for(i=0;i<n;i++)
printf("\t%d \t %d \t\t %d \t\t %d \n",i+1,ct[i],wa[i],tat[i]);
getch();
}

Output

Priority Program

#include<stdio.h>

main()

{

int p[20],bt[20],pri[20], wt[20],tat[20],i, k, n, temp; float wtavg, tatavg;



printf("Enter the number of processes --- "); scanf("%d",&n);

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

{
p[i] = i;

printf("Enter the Burst Time & Priority of Process %d --- ",i); scanf("%d %d",&bt[i], &pri[i]);
}

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

for(k=i+1;k<n;k++) if(pri[i] > pri[k])
{

temp=p[i];

p[i]=p[k];

p[k]=temp;

temp=bt[i];

bt[i]=bt[k];
bt[k]=temp;

temp=pri[i];

pri[i]=pri[k];
pri[k]=temp;

}

wtavg = wt[0] = 0; tatavg = tat[0] = bt[0];

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

wt[i] = wt[i-1] + bt[i-1]; tat[i] = tat[i-1] + bt[i];

wtavg = wtavg + wt[i]; tatavg = tatavg + tat[i];

}

printf("\nPROCESS\t\tPRIORITY\tBURST TIME\tWAITING TIME\tTURNAROUND TIME"); for(i=0;i<n;i++)

printf("\n%d \t\t %d \t\t %d \t\t %d \t\t %d ",p[i],pri[i],bt[i],wt[i],tat[i]);

printf("\nAverage Waiting Time is --- %f",wtavg/n); printf("\nAverage Turnaround Time is --- %f",tatavg/n); getch();
}

Output