c program for first come first serve scheduling
c program for first come first serve scheduling. This c program computes average and total
waiting time and turn around time of processes. c program for first come first serve gives
practical knowledge of how a operating system perform task scheduling.
c program for first come first serve scheduling
#include<stdio.h>
#include<conio.h>
void display();
void getdata();
void waitTime();
void turnAroundTime();
int n, a[100],b[100];
int main()
{
printf("***** FCFS ( FIRST COME FIRST SERVE ) SCHEDULING ******\n\n");
getdata();
display();
waitTime();
turnAroundTime();
getch();
}
void getdata()
{
char c;
printf("Enter the number of process ");
scanf("%d",&n);
printf("\nDo you need to enter the arrival time of process [y/n] or [Y/N]\n");
scanf("%s",&c);
for(int i=0; i<n; i++)
{
printf("Enter the %d process burst time : ",i+1);
scanf("%d",&b[i]);
if(c=='y' || c=='Y')
{
printf("Enter the %d process arrival time : ",i+1);
scanf("%d",&a[i]);
}
else
{
a[i]=0;
}
}
}
void display()
{
printf("\nPROCESS\tBURST TIME\tARRIVAL TIME6\n");
for(int i=0; i<n; i++)
{
printf(" %d\t %d\t %d\n",i+1,b[i],a[i]);
}
}
void waitTime()
{
int w[100];
float totalWait=0;
w[0]=0;
for(int i=1; i<n; i++)
{
w[i]=b[i-1]-a[i]+w[i-1];
totalWait=w[i]+totalWait;
}
printf("\nTotal Waiting time = %f",totalWait);
printf("\nAverage Waiting time = %f",totalWait);
}
void turnAroundTime()
{
int tat[100];
float totalTat=0;
tat[-1]=0;
for(int i=0; i<n; i++)
{
tat[i]=b[i]-a[i]+tat[i-1];
totalTat=totalTat+tat[i];
}
printf("\n\nTotal Turn Around Time(TAT) = %f",totalTat);
printf("\nAverage Turn Around Time Avg.(TAT) = %f",totalTat/n);
}
//CREATE A FILE AND STORE DATA IN IT IN C PROGRAM
#include<stdio.h>
int main(){
FILE *fp;
char ch;
fp=fopen("file.txt","w");
printf("\nEnter data to be stored in to the file:");
while((ch=getchar())!=EOF)
putc(ch,fp);
fclose(fp);
return 0;
}
//COPY DATA FROM ONE FILE TO ANOTHER FILE USING C PROGRAM#include<stdio.h>
int mai()
{
FILE *p,*q;
char file1[20],file2[20];
char ch;
printf("\nEnter the source file name to be copied:");
gets(file1);
p=fopen(file1,"r");
if(p==NULL)
{
printf("cannot open %s",file1);
exit(0);
}
printf("\nEnter the destination file name:");
gets(file2);
q=fopen(file2,"w");
if(q==NULL)
{
printf("cannot open %s",file2);
exit(0);
}
while((ch=getc(p))!=EOF)
putc(ch,q);
printf("\nCOMPLETED");
fclose(p);
fclose(q);
return 0;
}//DISPLAY SOURCE CODE AS OUTPUT IN C PROGRAM#include<stdio.h>
int main()
{
FILE *p;
char ch;
p=fopen("raja.c","r");
while((ch=getc(p))!=-1)
putchar(ch);
fclose(p);
return 0;
}//How to read a text file by c program#include<stdio.h>
int main()
{ char str[70];
FILE *p;
if((p=fopen("string.txt","r"))==NULL)
{
printf("\nUnable t open file string.txt");
exit(1);
}
while(fgets(str,70,p)!=NULL) puts(str);
fclose(p);
return 0;
}//WRITING OF ENTIRE ARRAY TO A FILE USING CPROGRAM#include<stdio.h>
int main()
{
FILE *p;
int i,a[10];
if((p=fopen("myfile.dat","wb"))==NULL)
{
printf("\nUnable to open file myfile.dat");
exit(1);
}
printf("\nEnter ten values, one value on each line\n");
for(i=0;i<10;i++)
scanf("%d",&a[i]);
fwrite(a,sizeof(a),1,p);
fclose(p);
return 0;
}//CONCATENATE MANY FILES AND STORE THEM IN A FILE IN C#include<stdio.h>
void concatenate(FILE *fp1,FILE *fp2,char *argv[],int argc);
int main(int argc,char *argv[])
{
FILE *fp1,*fp2;
concatenate(fp1,fp2,argv,argc);
return 0;
}void concatenate(FILE *fp1,FILE *fp2,char **argv,int argc)
{
int i,ch;
fp2=fopen("files","a");
for(i=1;i<argc-1;i++)
{
fp1=fopen(argv[i],"r");
while((ch=getc(fp1))!=EOF) putc(ch,fp2);
}
}//WRITE A C PROGRAM TO FIND SIZE OF A FILE#include <time.h>#include <sys\stat.h>
#include <stdio.h>
void main()
{
struct stat status;
FILE *fp;
fp=fopen("test.txt","r");
fstat(fileno(fp),&status);
clrscr();
printf("Size of file : %d",status.st_size);
printf("Drive name : %c",65+status.st_dev);
getch();
}Explanation: Function int fstat (char *, struct stat *) store the information of open file in form of structure struct statStructure struct stat has been defined in sys\stat.h asstruct stat { short st_dev, st_ino; short st_mode, st_nlink; int st_uid, st_gid; short st_rdev; long st_size, st_atime; long st_mtime, st_ctime; };Here(a)st_dev: It describe file has stored in which drive of your computer ,it returns a number.(b)st_mode: It describes various modes of file like file is read only, write only, folder, character file etc.(c)st_size: It tells the size of file in byte.(d)st_ctime:It tells last data of modification of the file in date format.Note: 65 is ASCII value of A .So after adding status.st_dev with 65 it will return appropriate drvie name as inyour computer.//How to read a text file by c program#include<stdio.h>
int main()
{
char str[70];
FILE *p;
if((p=fopen("string.txt","r"))==NULL)
{
printf("\nUnable t open file string.txt");
exit(1);
}
while(fgets(str,70,p)!=NULL) puts(str);
fclose(p);
return 0;
}//WRITING OF ENTIRE ARRAY TO A FILE USING C PROGRAM#include<stdio.h>
int main()
{
FILE *p;
int i,a[10];
if((p=fopen("myfile.dat","wb"))==NULL)
{
printf("\nUnable to open file myfile.dat");
exit(1);
}
printf("\nEnter ten values, one value on each line\n");
for(i=0;i<10;i++)
scanf("%d",&a[i]);
fwrite(a,sizeof(a),1,p);
fclose(p);
return 0;
}//CONCATENATE MANY FILES AND STORE THEM IN A FILE IN C#include<stdio.h>
void concatenate(FILE *fp1,FILE *fp2,char *argv[],int argc);
int main(int argc,char *argv[])
{
FILE *fp1,*fp2;
concatenate(fp1,fp2,argv,argc);
return 0;
}void concatenate(FILE *fp1,FILE *fp2,char **argv,int argc)
{
int i,ch; fp2=fopen("files","a");
for(i=1;i<argc-1;i++)
{
fp1=fopen(argv[i],"r");
while((ch=getc(fp1))!=EOF)
putc(ch,fp2);
}
}//CONCATENATE MANY FILES AND STORE THEM IN A FILE IN C#include<stdio.h>
void concatenate(FILE *fp1,FILE *fp2,char *argv[],int argc);
int main(int argc,char *argv[])
{
FILE *fp1,*fp2;
concatenate(fp1,fp2,argv,argc);
return 0;
}void concatenate(FILE *fp1,FILE *fp2,char **argv,int argc)
{
int i,ch;
fp2=fopen("files","a");
for(i=1;i<argc-1;i++)
{
fp1=fopen(argv[i],"r");
while((ch=getc(fp1))!=EOF)
putc(ch,fp2);
}
}/Write a c program to know given file is regular file, character special or it is directory?#include "time.h"
#include "sys\stat.h"
#include "stdio.h"
void main()
{
struct stat status;
FILE *fp;
stat("c:\\tc\\bin",&status);
clrscr();
if (status.st_mode & S_IFDIR)
printf("It is directory.\n");
if (status.st_mode & S_IFCHR)
printf("It is chracter file.");
if (status.st_mode & S_IFREG)
printf("It is reggular file.");
getch();
}Output: It is directory. Explanation: Function int stat (char *, struct stat *) store the information of open file in form of structure struct stat Structure struct stat has been defined in sys\stat.h asstruct stat { short st_dev, st_ino; short st_mode, st_nlink; int st_uid, st_gid; short st_rdev; long st_size, st_atime; long st_mtime, st_ctime; };Here(m)st_dev: It describe file has stored in which drive of your computer.(n)st_mode: It describes various modes of file like file is read only, write only, folder, character file etc.(o)st_size: It tells the size of file in byte.(p)St_ctime:It tells last data of modification of the file.There are some macro has been defined in sys\stat.hName Meaning S_IFMT File type mask S_IFDIR Directory S_IFIFO FIFO special S_IFCHR Character special S_IFBLK Block special S_IFREG Regular file S_IREAD Owner can read S_IWRITE Owner can write S_IEXEC Owner can executeSo masking or bitwise and operation between status.st_mode and S_IFDIR return true if it is directory and so on//Write a c program to know read/write permission of given file.#include "time.h"
#include "sys\stat.h"
#include "stdio.h"
void main()
{
struct stat status;
FILE *fp;
stat("test.txt",&status);
clrscr();
if (status.st_mode & S_IREAD)
printf("You have read permission.\n");
if (status.st_mode & S_IWRITE)
printf("You have write permission.");
getch();}//Write a c program to know the last date of modification of any file#include "time.h"
#include "sys\stat.h"
#include "stdio.h"
int main()
{
struct stat status;
FILE *fp;
fp=fopen("test.txt","r");
fstat(fileno(fp),&status);
printf("Last date of modification : %s",ctime(&status.st_ctime));
return 0;
}Explanation: Function int fstat(char *, struct stat *) store the information of open file in form of structure struct statStructure struct stat has been defined in sys\stat.h asstruct stat { short st_dev, st_ino; short st_mode, st_nlink; int st_uid, st_gid; short st_rdev; long st_size, st_atime; long st_mtime, st_ctime; }; Here(e)st_dev: It describe file has stored in which drive of your computer.(f)st_mode: It describes various modes of file like file is read only, write only, folder, character file etc.(g)st_size: It tells the size of file in byte.(h)st_ctime:It tells last data of modification of the file in date format.Function ctime convert date type in string format//Write a c program to find out the size and drive where file has stored of any given file?#include "time.h"
#include "sys\stat.h"
#include "stdio.h"
int main()
{
struct stat status;
FILE *fp;
fp=fopen("test.txt","r");
fstat(fileno(fp),&status);
printf("Size of file : %d",status.st_size);
printf("Drive name : %c",65+status.st_dev);
return 0;
}
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