C Program to Simulate Round Robin CPU Sceduling Algorithm

The round robin CPU scheduling algorithm is simulated using C program. The time slice or time quantum is read from the user.

Program:

#include<stdio.h>
struct process{



int burst,wait,comp,f;
}p[20]={0,0};
int main(){
int
n,i,j,totalwait=0,totalturn=0,quantum,flag=1,
time=0;
printf("\nEnter The No Of Process
:");
scanf("%d",&n);
printf("\nEnter The Quantum time (in ms)
:");
scanf("%d",&quantum);
for(i=0;i<n;i++){
printf("Enter The Burst Time (in ms) For
Process #%2d :",i+1);
scanf("%d",&p[i].burst);
p[i].f=1;
}
printf("\nOrder Of Execution \n");
printf("\nProcess \tStarting\tEnding\tRemaining");
printf("\n\tTime \tTime\tTime");
while(flag==1){
flag=0;
for(i=0;i<n;i++){
if(p[i].f==1){
flag=1;
j=quantum;
if((p[i].burst-p[i].comp)>quantum){
p[i].comp+=quantum;
}
else{
p[i].wait=time-p[i].comp;
j=p[i].burst-p[i].comp;
p[i].comp=p[i].burst;
p[i].f=0;
}
printf("\nprocess # %-3d %-10d %-10d %-10d",i+1,time,time+j,p[i].burst-
p[i].comp);
time+=j;
}}}
printf("\n\n------------------");
printf("\nProcess \t Waiting Time  TurnAround Time ");
for(i=0;i<n;i++){
printf("\nProcess # %-12d%-15d%-15d",i+1,p[i].wait,p[i].wait+p[i].burst);
totalwait=totalwait+p[i].wait;
totalturn=totalturn+p[i].wait+p[i].burst;
}
printf("\n\nAverage\n------------------");
printf("\nWaiting Time : %f ms",totalwait/(float)n);
printf("\nTurnAround Time : %f ms\n\n",totalturn/(float)n);
return 0;
}

C Program to Simulate Priority Scheduling CPU scheduling Algorithm

The following C program implements Simulation of  priority scheduling (CPU Scheduling algorithm). Each process or job is given a priority. The priority is represented using a positive integer. The priority increases as the value of the integer decreases.

Program:

#include<stdio.h>
struct process{



int burst,wait,no,priority;
}p[20]={0,0};
int main(){
int n,i,j,totalwait=0,totalturn=0;
printf("\nEnter The No Of Process :");
scanf("%d",&n);
for(i=0;i<n;i++){
printf("Enter The Burst Time (in ms) For Process #%2d :",i+1);
scanf("%d",&p[i].burst);
printf("Enter The Priority For Process #%2d :",i+1);
scanf("%d",&p[i].priority);
p[i].no=i+1;
}
for(i=0;i<n;i++)
for(j=0;j<n-i-1;j++)
if(p[j].priority>p[j+1].priority)
{
p[j].burst^=p[j+1].burst^=p[j].burst^=p[j+1].burst;
p[j].no^=p[j+1].no^=p[j].no^=p[j+1].no;
//Simple way to swap 2 var’s
p[j].priority^=p[j+1].priority^=p[j].priority^=p[j+1].priority;
//printf("j");
}
printf("\nProcess \t Starting\tEnding\tWaiting\tTurnAround ");
printf("\n\t Time\tTime\tTime\tTime ");
for(i=0;i<n;i++)
{
printf("\nProcess # %-11d%-10d%-10d%-10d%10d",p[i].no,p[i].wait,p[i].wait+p[i].burst,p[i].wait,p[i].wait+p[i].burst);
p[i+1].wait=p[i].wait+p[i].burst;
totalwait=totalwait+p[i].wait;
totalturn=totalturn+p[i].wait+p[i].burst;
}
printf("\n\nAverage\n---------");
printf("\nWaiting Time : %f ms",totalwait/(float)n);
printf("\nTurnAround Time : %f ms\n\n",totalturn/(float)n);
return 0;
}

Output:
Enter The No Of Process :3
Enter The Burst Time (in ms) For Process #1 :30
Enter The Priority For Process # 1 :2
Enter The Burst Time (in ms) For Process #2 :20
Enter The Priority For Process # 2 :1
Enter The Burst Time (in ms) For Process #3 :40
Enter The Priority For Process # 3 :3

Process          Starting  Ending  Waiting  TurnAround
                          Time        Time      Time          Time
Process # 2        0             20           0                20
Process # 1       20            50          20              50
Process # 3       50            90          50              90

Average
---------
Waiting Time : 23.333333 ms
TurnAround Time : 53.333333 ms

Simulation of Shortest Job First (SJF) CPU scheduling algorithm in C Language

This is a C program to simulate Shortest Job First (SJF) CPU scheduling algorithm. In Shortest Job first CPU scheduling algorithm, the process with  shortest CPU burst time is executed first. The following program is to simulate non preemptive SJF scheduling. Preemptive SJF CPU scheduling algorithm will be discussed in another post.

#include<stdio.h>
struct process
{
int burst,wait,no;
}p[20]={0,0};

int main()
{
int n,i,j,totalwait=0,totalturn=0;
printf("\nEnter The No Of Process :");
scanf("%d",&n);
for(i=0;i<n;i++)
  {
  printf("Enter The Burst Time (in ms) For Process #%2d :",i+1);
  scanf("%d",&p[i].burst);
  p[i].no=i+1;
  }

for(i=0;i<n;i++)
  for(j=0;j<n-i-1;j++)
    if(p[j].burst>p[j+1].burst)
      {
      p[j].burst^=p[j+1].burst^=p[j].burst^=p[j+1].burst;
      p[j].no^=p[j+1].no^=p[j].no^=p[j+1].no;
      }

printf("\nProcess \t Waiting Time TurnAround Time ");
for(i=0;i<n;i++)
  {
  printf("\nProcess # %-12d%-15d%-15d",p[i].no,p[i].wait,p[i].wait+p[i].burst);
  p[i+1].wait=p[i].wait+p[i].burst;
  totalwait=totalwait+p[i].wait;
  totalturn=totalturn+p[i].wait+p[i].burst;
  }
printf("\n\nAverage\n---------");
printf("\nWaiting Time : %f ms",totalwait/(float)n);
printf("\nTurnAround Time : %f ms\n\n",totalturn/(float)n);
return 0;

}

Output:

Enter The No Of Process :3
Enter The Burst Time (in ms) For Process # 1 :20
Enter The Burst Time (in ms) For Process # 2 :30
Enter The Burst Time (in ms) For Process # 3 :10
Process          Waiting Time     TurnAround Time
Process # 3          0                           10
Process # 1        10                            30
Process # 2        30                            60

Average---------
Waiting Time : 13.333333 ms
TurnAround Time : 33.333333 ms

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C Program to Simulate ls Command in Linux
C Program to Simulate Round Robin CPU Scheduling Algorithm
C Program to Simulate Priority CPU Scheduling Algorithm
C Program to Simulate First Come First Serve (FCFS) CPU Scheduling Algorithm
C Program to Simulate rmdir Command or Delete Directory
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Simulation of FCFS CPU Scheduling Algorithm in C

This is a C program to simulate First come first served (FCFS) CPU scheduling algorithm. First come first served algorithm serves each processes (or jobs) in the order of arrival. The process with lowest arrival time is executed first.

Program:
#include<stdio.h>
struct process
{
int burst,wait;
}p[20]={0,0};



int main()
{
int n,i,totalwait=0,totalturn=0;
printf("\nEnter The No Of Process :");
scanf("%d",&n);
for(i=0;i<n;i++)
{
printf("Enter The Burst Time (in ms) For Process #%2d :",i+1);
scanf("%d",&p[i].burst);
}
printf("\nProcess \t Waiting Time\tTurnAround Time ");
printf("\n\t (in ms)\t(in ms)");
for(i=0;i<n;i++)
{
printf("\nProcess # %-12d%-15d%-15d",i+1,p[i].wait,p[i].wait+p[i].burst);
p[i+1].wait=p[i].wait+p[i].burst;
totalwait=totalwait+p[i].wait;
totalturn=totalturn+p[i].wait+p[i].burst;
}
printf("\n\nAVERAGE\n--------- ");
printf("\nWaiting Time : %f ms",totalwait/(float)n);
printf("\nTurnAround Time : %f ms\n\n",totalturn/(float)n);
return 0;
}

Output:
Enter The No Of Process :3
Enter The Burst Time (in ms) For Process # 1 :10
Enter The Burst Time (in ms) For Process # 2 :30
Enter The Burst Time (in ms) For Process # 3 :20
Process    Waiting Time     Turn Around Time
                     (in ms)                      (in ms)
Process # 1     0                               10
Process # 2    10                              40
Process # 3    40                              60

AVERAGE
---------
Waiting Time : 16.666667 ms
TurnAround Time : 36.666667 ms

C Program to Simulate the ls Command in Linux Operating system

This is a c program to do Simulation of ls Command in linux. The ls command lists all the contents of the directory including filse and sub-directories. The following c program in simulates the ls command.

#include<stdio.h>
#include<dirent.h>
main()
{
char dirname[10];
DIR*p;
struct dirent *d;
printf("Enter directory name\n");
scanf("%s",dirname);
p=opendir(dirname);
if(p==NULL)
  {
  perror("Cannot find directory");
  exit(-1);
  }
while(d=readdir(p))
  printf("%s\n",d->d_name);
}

Related Posts:

C Program to Simulate ls Command in Linux
C Program to Simulate Round Robin CPU Scheduling Algorithm
C Program to Simulate Priority CPU Scheduling Algorithm
C Program to Simulate First Come First Serve (FCFS) CPU Scheduling Algorithm
C Program to Simulate rmdir Command or Delete Directory
C Program to Open, Read and Write Files
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C Program to Simulate grep Command in Linux

This post contains C program to simulate grep command in Linux or Unix operating systems

Simulation of  grep command in Linux

#include<stdio.h>
#include<string.h>
void main()
{
char fn[10],pat[10],temp[200];
FILE *fp;
printf("Enter file name\n");
scanf("%s",fn);
printf("Enter pattern to be searched\n");
scanf("%s",pat);
fp=fopen(fn,"r");
while(!feof(fp))
{
fgets(temp,1000,fp);
if(strstr(temp,pat))
  printf("%s",temp);
}
fclose(fp);
}

Related Posts:

C Program to Simulate ls Command in Linux
C Program to Simulate Round Robin CPU Scheduling Algorithm
C Program to Simulate Priority CPU Scheduling Algorithm
C Program to Simulate Shortest Job First (SJF) CPU Scheduling Algorithm
C Program to Simulate First Come First Serve (FCFS) CPU Scheduling Algorithm
C Program to Simulate rmdir Command or Delete Directory
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C Program to Remove (Delete) a Directory using LINUX System Calls

This is a C program to delete  or remove a directory using the system calls in Linux or Unix operating systems. The program make use of the remove() system call in Linux.

#include<stdio.h>
#include<fcntl.h>
main()
{



char fn[10];
printf("Enter source filename\n");
scanf("%s",fn);
if(remove(fn)==0)
printf("File removed\n");
else
printf("File cannot be removed\n");
}

C Program to open, read and write files and perform file copy operation usingSystem Calls in UNIX

Write a program to open, read and write files and perform file copy operation. This program show how to open, read, write and copy files using Linux or Unix system calls like open(), read() and write().

#include<stdio.h>
#include<fcntl.h>
main()
{


char buff[1000],fn1[10],fn2[10];
int fd1,fd2,n;
printf("Enter source filename\n");
scanf("%s",fn1);
printf("Enter destination file name\n");
scanf("%s",fn2);
fd1=open(fn1,O_RDONLY);
n=read(fd1,buff,1000);
fd2=open(fn2,O_CREAT|O_WRONLY);
n=write(fd2,buff,n);
close(fd1);
close(fd2);
}

C Program to Open, Read and Write a file using System Calls

This is a C program to open , read and write files using system calls in Linux (UNIX) operating systems. The system calls open(), read() and write() are used in the C program to open, read and write files in Unix/Linux operating systems.

#include<stdio.h>
#include<fcntl.h>
main()
{


char buff[100],fn[10];
int fd,n;
printf("Enter file name\n");
scanf("%s",fn);
fd=open(fn,O_RDONLY);
n=read(fd,buff,100);
n=write(1,buff,n);
close(fd);
}

Using System calls in C Program to rename a Directory in Linux

C Program to rename a directory in Unix or Linux operating systems using system call rename().

#include<stdio.h>
main()
{

char s[10],d[10];
printf("Enter source Dir Name:\n");
scanf("%s",s);
printf("Enter New Dir Name:\n");
scanf("%s",d);
if(rename(s,d)==-1)
perror("Can't be changed\n");
else
printf("%s is changed to %s\n\n",s,d);
}