/*CSEMATTERBLOGSPOT.IN
Write a program in C to implement priority based CPU scheduling algo
calculate avg. waiting time & average turn around time*/
#include<stdio.h>
#include<conio.h>
#include<graphics.h>
int main()
{
int gd=DETECT,gm,i,j,k,n,b,count=0,arr[20],prio[20],bt[20],wt[20],tat[20];
float avg_wt,avg_tat,sum_wt=0.0,sum_tat=0.0;
initgraph(&gd,&gm,"C:\TC\BIN");
printf("Enter the no. of processes ");
scanf("%d",&n);
printf("Enter the burst time of processes \n");
for(i=0;i<n;i++)
scanf("%d",&bt[i]);
printf("Enter priority of processes \n");
for(i=0;i<n;i++)
{ scanf("%d",&prio[i]);
arr[i]=prio[i];}
for(i=0;i<=(n-2);i++)
{for(j=0;j<=((n-2)-i);j++)
{ if(arr[j]>arr[j+1])
{
b=arr[j];
arr[j]=arr[j+1];
arr[j+1]=b;
}} }
wt[0]=0;
tat[0]=0;
for(i=0;i<n;i++)
{ for(j=0;j<n;j++)
{ if(arr[i]!=prio[j])
count=count+1;
else
break;}
wt[i+1]=bt[count]+wt[i];
tat[i+1]=bt[count]+tat[i];
count=0; }
for(i=0;i<n;i++)
sum_wt=sum_wt+wt[i];
for(i=0;i<(n+1);i++)
sum_tat=sum_tat+tat[i];
avg_wt=(sum_wt/(float)n);
avg_tat=(sum_tat/(float)n);
printf("Process_no. Burst_Time Priority Waiting_Time Turn_Around_Time \n");
for(i=0;i<n;i++)
{
printf("P%d\t\t%d\t%d\t\t%d\t\t%d\n",i,bt[i],prio[i],wt[i],tat[i+1]);}
printf("Average waiting time is: %f \n",avg_wt);
printf("Average turn around time is: %f",avg_tat);
printf("\n\n \t GANTT CHART \n");
for(i=0;i<n;i++)
printf("P%d \t",i);
printf("\n");
for(i=0;i<n;i++)
{
printf("%d \t",wt[i]);
}
rectangle(2,300,270,320);
getch();
closegraph();
}
/* OUTPUT
Enter the no. of processes 5
Enter the burst time of processes
12 8 4 6 10
Enter priority of processes
5 1 2 4 3
Process_no. Burst_Time Priority Waiting_Time Turn_Around_Time
P1 8 1 0 8
P2 4 2 8 12
P4 10 3 12 22
P3 6 4 22 28
P0 12 5 28 40
Average waiting time is 14.00000
Average turn around time is 22.00000
GANTT CHART
||P1|| ||P2|| ||P4|| ||P3|| ||P0||
0 8 12 22 28 40*/
