Write a program in high level language to demonstrate the operation of the following CPU scheduling algorithms.

First Come First Serve

ALGORITHM:

1.      Start

2.      Get the number of processes

3.       

CODE:

#include

#include

void main()

{

     clrscr();

     int Bt[10],At[10],start[10],fin [10],TAT[10],wt[10], n,p[10],i;

     float avgwt,avgtat,totwt,tottat;

     printf("\n Enter number of Processes:");

     scanf("%d",&n);

     for(i=0;i

     {

                 printf("\n Input processes name,Arrival Time &Burst Time ");

                 scanf("%d %d %d",&p[i],&at[i],&bt[i] );

     }

     start[0]=at[0];

     fin [0]=start[0]+bt[0];

     wt[0]=0;

     TAT[0]=fin [0]-at[0];

     tottat=TAT[0];

     for(i=1;i

     {

         start[i]=fin [i-1];

         fin [i]=start[i]+bt[i];

         wt [i]=fin [i-1]-at[i];

         TAT[i]=fin [i]-at[i];

         totwt+= wt[i];

         tottat+=+TAT[i];

     }

     avgwt=totwt/n;

     avgtat=tottat/n;

     printf("Pname\tArrive time\tBurst time\tStart\tTAT\tFinish");

     for(i=0;i

     {

                 printf("\n%d\t%d\t\t%d\t\t%d\t%d\t%d",p[i],at[i],bt[i],start[i],TAT[i],fin [i]);

      }

      printf("\nAverage Waiting=%f",avgwt);

      printf("\nAverage Turn Over Around=%f",avgtat);

     getch();

}

Shortest Job First

ALGORITHM:

CODE:

#include

#include

void main()

{

     clrscr();

     int bt[10],at[10],start[10],fin [10],TAT[10],wt[10], n,p[10],i,j,temp;

     float avgwt,avgtat,totwt,tottat;

     printf("\n Enter number of Processes:");

     scanf("%d",&n);

     for(i=0;i

     {

                 printf("\n Input processes name,Arrival Time &Burst Time ");

                 scanf("%d %d %d",&p[i],&at[i],&bt[i] );

     }

     for(i=0;i

     {

                 for(j=i+1;j

                 {

                             if(bt[i]>bt[j])

                             {

                                         temp=bt[i];

                                         bt[i]=bt[j];

                                         bt[j]=temp;

                                         temp=p[i];

                                         p[i]=p[j];

                                         p[j]=temp;

                                         temp=at[i];

                                         at[i]=at[j];

                                         at[j]=temp;

                             }

                 }

     }

     start[0]=at[0];

     fin [0]=start[0]+bt[0];

     wt[0]=0;

     TAT[0]=fin [0]-at[0];

     tottat=TAT[0];

     for(i=1;i

     {

               start[i]=fin [i-1];

               fin [i]=start[i]+bt[i];

               wt [i]=fin [i-1]-at[i];

               TAT[i]=fin [i]-at[i];

               totwt+= wt[i];

               tottat+=+TAT[i];

     }

     avgwt=totwt/n;

     avgtat=tottat/n;

     printf("Pname\tArrive time\tBurst time\tStart\tTAT\tFinish");

     for(i=0;i

     {

                 printf("\n%d\t%d\t\t%d\t\t%d\t%d\t%d",p[i],at[i],bt[i],start[i],TAT[i],fin [i]);

      }

      printf("\nAverage Waiting=%f",avgwt);

      printf("\nAverage Turn Over Around=%f",avgtat);

     getch();

}

Round Robin

ALGORITHM:

CODE:

#include

#include

#include

#define m 10

void main()

{

         clrscr();

         int bt[m],start=0,est,c, n,p[m],i,q;

         printf("\nEnter the number of Processes:");

         scanf("%d",&n);

         printf("Enter Quantum");

         scanf("%d",&q);

         for(i=0;i

         {

                     printf("Enter Process name,Burst Time ");

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

         }

         do{

                     for(i=0;i

                     {

                                 if(bt[i]!=0){

                                             est=start+q;

                                             start=est;

                                             printf("\n%d -> %d",i+1,q);

                                             if(bt[i]>0&&bt[i]>=q)

                                                         bt[i]=bt[i]-q;

                                             else

                                                         bt[i]=0;

                     }

                     for(i=0;i

                     {

                                 if(bt[i]==0)

                                             c++;

                     }

         }while(c!=n);

        printf("\n Total Time Estimated=%d",start);

       getch();

}

Priority

ALGORITHM:

CODE:

#include

#include

#define m 10

void main()

{

         clrscr();

         int bt[m],at[m],start[m],fin [m],TAT[m],wt[m],p[m],pr[m],n,i,j,temp;

         float avgwt,avgtat,totwt,tottat;

         printf("\n Enter number of Processes:");

         scanf("%d",&n);

         for(i=0;i

         {

                     printf("\n Enter Process name,Arrival Time,Burst Time and Priority ");

                     scanf("%d %d %d %d",&p[i],&at[i],&bt[i],&pr[i]);

         }

         for(i=0;i

         {

                     for(j=i+1;j

                     {

                                 if(pr[i]>pr[j])

                                 {

                                             temp=pr[i];

                                             pr[i]=pr[j];

                                             pr[j]=temp;

                                             temp=bt[i];

                                             bt[i]=bt[j];

                                             bt[j]=temp;

                                             temp=p[i];

                                             p[i]=p[j];

                                             p[j]=temp;

                                             temp=at[i];

                                             at[i]=at[j];

                                             at[j]=temp;

                                 }

                     }

         }

         start[0]=at[0];

         fin [0]=start[0]+bt[0];

         wt[0]=0;

         TAT[0]=fin [0]-at[0];

         tottat=TAT[0];

         for(i=1;i

         {

      start[i]=fin [i-1];

      fin [i]=start[i]+bt[i];

      wt [i]=fin [i-1]-at[i];

      TAT[i]=fin [i]-at[i];

      totwt+= wt[i];

      tottat+=+TAT[i];

         }

         avgwt=totwt/n;

         avgtat=tottat/n;

         printf("Pname\tArrive time\tBurst time\tPriority\tWaiting time\tTAT");

         for(i=0;i

         {

                     printf("\n%d\t%d\t\t%d\t\t%d\t\t%d\t\t%d",p[i],at[i],bt[i],pr[i],wt[i],TAT[i]);

          }

          printf("\nAverage Waiting=%f",avgwt);

          printf("\nAverage Turn Over Around=%f",avgtat);

         getch();

}