Write a program to simulate Linked file allocation method.

 

Write a program to simulate Linked file allocation method. Assume disk with n number of blocks. Give value of n as input. Write menu driver program with menu options as mentioned above and implement each option.

#include<stdio.h>

#include<stdlib.h>

#include<string.h>

#define MAX 10

typedef struct dir

{

 char fname[20];

 int start;

 struct dir *next;

}NODE;

NODE *head,*last;

int n,bit[MAX],fb=0;

void init()

{

 int i;

 printf("Enter total no.of disk blocks:");

 scanf("%d",&n);

 for(i=0;i<n;i++)

 {

  bit[i]=rand()%2;

}

}

void show_bitvector()

{

 int i;

 for(i=0;i<n;i++)

  printf("%d ",bit[i]);

 printf("\n");

}

void show_dir()

{

 NODE *temp;

 int i;

for(temp=head;temp!=NULL;temp=temp->next)

{

printf("%d->",temp->start);

}

printf("NULL\n");

}

void create()

{

 NODE *p;

 char fname[20];

 int i,j,nob;

int fb=0;

 printf("Enter file name:");

 scanf("%s",fname);

 printf("Enter no.of blocks:");

 scanf("%d",&nob);

 

 for(i=0;i<n;i++)

 {

  if(bit[i]==0) 

  fb++; 

 }

 

if(nob>fb)

 {

  printf("Failed to create file %s\n",fname);

  return;

 }

 else

 {

for(i=0;i<n;i++)

{

if(bit[i]==0 && nob!=0) 

{

p = (NODE*)malloc(sizeof(NODE));

strcpy(p->fname,fname);

nob--;bit[i]=1;

p->start=i;

p->next=NULL;

  if(head==NULL)

  head=p;

else

  last->next=p;

  last=p;

 

}

}

printf("File %s created successully.\n",fname);

 } 

}

int main()

{

 int ch;

 init();

 while(1)

 {

  printf("1.Show bit vector\n");

  printf("2.Create new file\n");

  printf("3.Show directory\n");

  printf("4.Delete file\n");

  printf("5.Exit\n");

  printf("Enter your choice (1-5):");

  scanf("%d",&ch);

  switch(ch)

  {

  case 1:show_bitvector(); break;

  case 2: create(); break;

  case 3:show_dir(); break;

  case 4: delete();break;

  case 5: exit(0);

  }

 }

 return 0;

}