write a C Program to implement Round Robin algorithm - Computer Programming

# Computer Programming

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## Thursday, October 6, 2011

/*Program to implement Round Robin algorithm*/
#include<stdio.h>
#include<conio.h>
struct process
{
char na[20];
int at,bt,ft,tat,rem;
float ntat;
}Q[5],temp;
int rr[20],q,x,k;
main()
{
int f,r,n,i,j,tt=0,qt,t,flag,wt=0;
float awt=0,antat=0,atat=0;
clrscr();
printf("Enter the no. of jobs:");
scanf("%d",&n);
for(r=0;r<n;r++)
{
printf("Enter process name,arrival time and burst time:");
scanf("%s%d%d",Q[r].na,&Q[r].at,&Q[r].bt);
}
printf("Enter quantum:");
scanf("%d",&qt);
for(i=0;i<n;i++)
{
for(j=i+1;j<n;j++)
{
if(Q[i].at>Q[j].at)
{
temp=Q[i];
Q[i]=Q[j];
Q[j]=temp;
}
}
}
for(i=0;i<n;i++)
{
Q[i].rem=Q[i].bt;
Q[i].ft=0;
}
tt=0;
q=0;
rr[q]=0;
do
{
for(j=0;j<n;j++)
if(tt>=Q[j].at)
{
x=0;
for(k=0;k<=q;k++)
if(rr[k]==j)
x++;
if(x==0)
{
q++;
rr[q]=j;
}
}
if(q==0)
i=0;
if(Q[i].rem==0)
i++;
if(i>q)
i=(i-1)%q;
if(i<=q)
{
if(Q[i].rem>0)
{
if(Q[i].rem<qt)
{
tt+=Q[i].rem;
Q[i].rem=0;
}
else
{
tt+=qt;
Q[i].rem-=qt;
}
Q[i].ft=tt;
}
i++;
}
flag=0;
for(j=0;j<n;j++)
if(Q[j].rem>0)
flag++;
}while(flag!=0);
clrscr();
printf("\n\n\t\tROUND ROBIN ALGORITHM");
printf("\n***************************");
printf("\nprocesses Arrival time burst time finish time tat wt ntat");
for(f=0;f<n;f++)
{
wt=Q[f].ft-Q[f].bt-Q[f].at;
Q[f].tat=Q[f].ft-Q[f].at;
Q[f].ntat=(float)Q[f].tat/Q[f].bt;
antat+=Q[f].ntat;
atat+=Q[f].tat;
awt+=wt;
printf("\n\t%s\t%d\t\t%d\t%d\t%d\t%d %f",
Q[f].na,Q[f].at,Q[f].bt,Q[f].ft,Q[f].tat,wt,Q[f].ntat);
}
antat/=n;
atat/=n;
awt/=n;
printf("\nAverage tat is %f",atat);
printf("\nAverage normalised tat is %f",antat);
printf("\n average waiting time is %f",awt);
getch();    }