CodeBhavya

ADVANCED DATA STRUCTURES PROGRAM • LEVEL 19 — FILES AND FILE ORGANIZATION

Reuse Deleted Record Slots with a Free List

Learn how to reuse deleted record slots with a free list using a clear C program.

AdvancedRecord organizationSecondary storage

PROBLEM UNDERSTANDING

Input and expected output

Sample input
No input required
Sample output
Reused slot = 3 Next free = 1

COMPLETE C PROGRAM

Complete C implementation

ads-file-free-list-reuse.c
Open in compiler
#include <stdio.h>

int main(void)
{
    int next_free[]={-1,-1,-1,-1},free_head=-1;next_free[1]=free_head;free_head=1;next_free[3]=free_head;free_head=3;int reused=free_head;free_head=next_free[free_head];printf("Reused slot = %d Next free = %d\n",reused,free_head);return 0;
}

GUIDED CODE TOUR • NOT LIVE EXECUTION

Study the program line by line

Use the real compiler button above to run and debug with different inputs.

CURRENT STEP

Select Start to walk through the important lines.

SELECTED LINE

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EXPECTED OUTPUT FOR THE SAMPLE

Reused slot = 3 Next free = 1
0%Step 0 of 0

PROGRAM EXPLANATION

Algorithm and explanation

  1. Read the required input values.
  2. Chain deleted slots and allocate the free-list head before appending new storage.
  3. Display the computed result.

Chain deleted slots and allocate the free-list head before appending new storage.

EFFICIENCY

Time and space complexity

Time complexity

O(1) deletion and reuse

Auxiliary space

O(deleted slots)

DEBUGGING CHECKLIST

Common mistakes

Check this

Use the correct format specifier for every variable.

Check this

Initialize variables before using their values.

Check this

Check braces, semicolons and input order carefully.

Try it yourself

Practice: Run the program with the sample input, predict its output, and then test one boundary case of your own.