Contiguous (Oparating system)

 #include<stdio.h>

#include<stdlib.h>

#include<conio.h>

#include<string.h>

#include<malloc.h>

#define newdir (struct fat *)malloc(sizeof(struct fat))

#define newnode (struct fbl *)malloc(sizeof(struct fbl))

struct fat

{

 char fname[30];

 int start,length,flag;

 struct fat *link;

}*first=NULL;

struct fbl

{

 int start,length;

 struct fbl *link;

}*f1=NULL;

int blocks;

void disp_dir();

void disp_free_space();

struct fat *append(struct fat *);

int main()

{

 int ch,bno,f;

 char fn[30];

 struct fbl *p;struct fat *q;

 clrscr();

 printf("Enter number of blocks:");

 scanf("%d",&blocks);

 f1=newnode;

 f1->start=0;

 f1->length=blocks;

 f1->link=NULL;

 while(1)

 {

  f=1;

  printf("\n1.INSERTION\n2.DELETION\n3.DISPLAY\n4.EXIT\nEnter your choice:");

  scanf("%d",&ch);

  switch(ch)

  {

   case 1:printf("Enter the file name:");

   scanf("%s",fn);

   printf("Enter the file size in number of blocks:");

   scanf("%d",&bno);

   for(p=f1;p!=NULL;p=p->link)

   {

           if(p->length>=bno)break;

   }

   if(p==NULL)printf("Not enough space...");

   else

   {

           q=newdir;

    strcpy(q->fname,fn);

    q->length=bno;

    q->start=p->start;

    q->flag=0;

    q->link=NULL;

    first=append(q);

    p->start+=bno;

    p->length-=bno;

    printf("File is placed in free space...");

   }break;

   case 2:printf("Enter the file name to be deleted:");

   scanf("%s",fn);

   for(q=first;q!=NULL;q=q->link)

   {

       if(strcmp(q->fname,fn)==0){f=0;break;}

   }

   if(f==1)printf("The given file doesn't exist...");

   else

   {//printf("%s",q->fname);

    q->flag=1;

    p=newnode;

    p->start=q->start;

    p->length=q->length;

    p->link=NULL;

           for(;f1->link!=NULL;f1=f1->link);

    f1->link=p;

    printf("The given file is deleted from the disk...");

   }break;

   case 3:disp_dir();disp_free_space();break;

   case 4:exit(0);

  }

 }

 getch();

 return 0;

}

void disp_dir()

{

 struct fat *p;

 printf("\nDisk List:");

 printf("\nName\tStart\tLength");

 for(p=first;p!=NULL;p=p->link)

 {

  if(p->flag==0)printf("\n%s\t%d\t%d",p->fname,p->start,p->length);

 }

}void disp_free_space(){

 struct fbl *q;

 printf("\nFree Block-space List:");

 printf("\nStart\tLength");

 for(q=f1;q!=NULL;q=q->link)

 {printf("\n%d\t%d",q->start,q->length);}

}

struct fat *append(struct fat *f)

{

 struct fat *s;

 if(first==NULL)

 {

  first=newdir;

  first=f;

 }else{

  for(s=first;s->link!=NULL;s=s->link);

  s->link=f;

  s=f;

 }

 return first;

}