Linked File Allocation 1

Write a C program to implement linked file allocation by considering the following assumptions and given sample input and output.

Note: 
Assume that the free disk space that is available is between 1 and 100. And the blocks are linked in order i.e 1 is linked to 2, 2 is linked to 3 ….. and 99 is linked to 100. If a certain block is allocated to a file, say 4, then 3 will be linked to 5.

Assume that 'n' blocks are already allocated to files. Write a C program to allocate space for 1 file using Linked File Allocation. Always assume that the starting block is a free block.

 

Input format:

Input consists of a number of blocks already allocated ( int ), n allocated block numbers ( int ), name ( string), Start of the block ( int ), and length ( int ) of the file to be allocated disk space. Enter allocated block numbers in ascending order.

 

Output format:

The output consists of file allocation details using linked allocation technique after allocating the input file.

[ Refer Sample Input and Output for further details ]
 

Sample Input and Output:

[ All text in bold corresponds to input ]

Enter the number of allocated blocks

6

Enter the block numbers of allocated blocks

4

6

7

10

22

27

Enter the name of the file

F1

Enter the starting block allocated to the file

3

Enter the length of the file

5

F1 File Allocation Details

3-> Allocated to F1

4-> Already Allocated

5-> Allocated to F1

6-> Already Allocated

7-> Already Allocated

8-> Allocated to F1

9-> Allocated to F1

10-> Already Allocated

11-> Allocated to F1

Answer:

#include<stdio.h>
int main()
{
    int n,bl,arr[100],le,k,start,i;
    char name[100];
    printf("Enter the number of allocated blocks\n");
    scanf("%d",&n);
    printf("Enter the block numbers of allocated blocks\n");
    for(i=0;i<100;i++){
        arr[i]=0;
    }
    for(i=1;i<=n;i++)
    {
        scanf("%d",&bl);
        arr[bl]=bl;
    }
    printf("Enter the name of the file\n");
    scanf("%s",name);
    printf("Enter the starting block allocated to the file\n");
    scanf("%d",&start);
    printf("Enter the length of the file\n");
    scanf("%d",&le);
    printf("%s File Allocation Details\n",name);
    for(i=start,k=0;i<100 && k<le;i++)
    {
        if(arr[i]==0){
            printf("%d - Allocated to %s\n",i,name);
            k++;
        }
        else{
            printf("%d - Already Allocated\n",i);
        }
    }
}