How to write a c Program to Simulation program for FCFS ( First Come First Serve ) in C Programming Language ?
Solution:/*
Write the simulation program for FCFS. The arrival time and first
CPU bursts of different jobs should be input to the system.
The output should give the Gantt Chart, Turnaround Time and Waiting time for each process and average
times.
*/
#include<stdio.h>
struct Input
{
char pname[10];
int bt,at,ct,tbt;
}tab[5];
struct Sequence
{
int start,end;
char pname[10];
}seq[100],seq1[20];
int finish,time,n,k,prev;
void getinput()
{
int i;
clrscr();
printf("\nEnter No.of Processes:");
scanf("%d",&n);
for(i=0;i<n;i++)
{
printf("Process name:");
scanf("%s",tab[i].pname);
printf("Burst time:");
scanf("%d",&tab[i].bt);
printf("Arrival time:");
scanf("%d",&tab[i].at);
tab[i].tbt = tab[i].bt;
}
}
void printinput()
{
int i;
printf("\n\n\nProcess\tBT\tAT");
for(i=0;i<n;i++)
printf("\n%s\t%d\t%d",tab[i].pname,tab[i].tbt,tab[i].at);
getch();
}
void bubble()
{
struct Input t;
int i,j;
for(i=0;i<n;i++)
for(j=0;j< (n-1)-i;j++)
if(tab[j].at>tab[j+1].at)
{
t = tab[j];
tab[j] = tab[j+1];
tab[j+1] = t;
}
}
void printoutput()
{
int i;
float AvgTAT=0,AvgWT=0;
clrscr();
printf("\n *******Final Table*********");
printf("\n\nProcess\tAT\tBT\tCT\tTAT\tWT");
for(i=0;i<n;i++)
{
printf("\n\n%s\t%d\t%d\t%d\t%d\t%d",tab[i].pname,
tab[i].at,
tab[i].bt,
tab[i].ct,
tab[i].ct-tab[i].at,
tab[i].ct-tab[i].at-tab[i].bt);
AvgTAT += tab[i].ct-tab[i].at;
AvgWT += tab[i].ct-tab[i].at-tab[i].bt;
}
AvgTAT/=n;
AvgWT/=n;
printf("\n\nAverage TAT = %f",AvgTAT);
printf("\n\nAverage WT = %f",AvgWT);
getch();
}
int arrived(int t)
{
int i;
for(i=0;i<n;i++)
if(tab[i].at<=t && tab[i].tbt!=0)
return 1;
return 0;
}
void processinput()
{
int i=0,j;
finish = k = 0;
time=tab[0].at;
while(finish!=n)
{
if(arrived(time))
{
if(tab[i].tbt!=0)
{
for(j=0;j<tab[i].bt;j++)
{
time++;
tab[i].tbt--;
printinput();
seq[k].start=prev;
seq[k].end = time;
strcpy(seq[k++].pname,tab[i].pname);
prev = time;
tab[i].ct=time;
if(tab[i].tbt==0)
{
finish++;
break;
}
}
}
}
else
{
time++;
seq[k].start=prev;
seq[k].end = time;
strcpy(seq[k++].pname,"*");
prev = time;
}
if(time < tab[(i+1)%n].at)
{
i=0;
}
else
i = (i+1)%n;
}
}
void ganttchart()
{
int i,j=1;
clrscr();
seq1[0] = seq[0];
printf("\n ******Gantt Chart*******");
for(i=1;i<k;i++)
{
if(strcmp(seq1[j-1].pname,seq[i].pname)==0)
seq1[j-1].end = seq[i].end;
else
seq1[j++] = seq[i];
}
for(i=0;i<j;i++)
printf("\n\n%d\t%s\t%d",seq1[i].start,seq1[i].pname,seq1[i].end);
getch();
}
void main()
{
int i;
getinput();
printf("\nEntered data-: ");
printinput();
bubble();
printf("\n\nData after sorting according to arrival time-: ");
printinput();
processinput();
printoutput();
ganttchart();
}