Coding of priority for operating system

PRIORITY 

#include <stdio.h>
#include<string.h>

void main()
{
int et[20],at[10],n,i,j,temp,p[10],st[10],ft[10],wt[10],ta[10];
int totwt=0,totta=0;
float awt,ata;
char pn[10][10],t[10];

printf("enter the no of process");
scanf("%d",&n);
for(i=0;i<n;i++)
{
printf("Pname,arrival time,execution time&priority");
scanf("%s%d%d%d",pn[i],&at[i],&et[i],&p[i]);
}
for(i=0;i<n;i++)
for(j=0;j<n;j++)
{
if(p[i]<p[j])
{
temp=p[i];
p[i]=p[j];
p[j]=temp;
temp=at[i];
at[i]=at[j];
at[j]=temp;
temp=et[i];
et[i]=et[j];
et[j]=temp;
strcpy(t,pn[i]);
strcpy(pn[i],pn[j]);
strcpy(pn[j],t);
}
}
for(i=0;i<n;i++)
{
if(i==0)
{
st[i]=at[i];
wt[i]=st[i]-at[i];
ft[i]=st[i]+et[i];
ta[i]=ft[i]-at[i];
}
else
{
st[i]=ft[i-1];
wt[i]=st[i]-at[i];
ft[i]=st[i]+et[i];
ta[i]=ft[i]-at[i];
}
totwt+=wt[i];
totta+=ta[i];
}
awt=(float)totwt/n;
ata=(float)totta/n;
printf("\nPname\tarrivaltime\texecutiontime\tpriority\tturnaroundtime");
for(i=0;i<n;i++)
printf("\n%s\t%5d\t\t%5d\t\t%5d\t\t%5d",pn[i],at[i],et[i],p[i],ta[i]);
printf("\naverage waiting time is:%f",awt);
printf("\naverage turnaround time is:%f",ata);

}