Pack A: CBSE Class 12 Board Pack

Everything extra the CBSE Computer Science (083) board asks: binary files, CSV, stack, SQL and Python-MySQL, plus board-style drills.

1. Binary files with pickle: pickle.dump(obj, f) writes one object to a file opened in wb/ab; pickle.load(f) reads one back, so loop until EOFError.
2. Binary file programs: search, append, update: Search with a found flag; append with ab; update or delete by reading all records, changing the list, and rewriting with wb.
3. CSV files, board style: Open CSV files with newline=""; writerow/writerows write, reader reads lists of strings; skip the header with next() and convert before maths.
4. Stack programs: A stack is LIFO: push with append(), pop with pop(), peek with [-1], and always check for an empty stack before popping.
5. SQL you can run: queries for the board: SELECT … FROM … WHERE … GROUP BY … HAVING … ORDER BY; use IS NULL, LIKE with % and , and never UPDATE or DELETE without WHERE unless you mean every row.
6. Python + MySQL connectivity: connect → cursor → execute (with %s and a tuple) → commit() for changes or fetchone()/fetchall() for reading → close; rowcount counts affected or fetched rows.
7. Board question types: output, errors, assertion-reason: Trace with a table; goes right to left; randint includes both ends; except clauses are tried top to bottom; in A-R, judge A and R separately, then ask "A because R?".
8. Practical file, project and viva: Practical = lab test 12 + report file 7 + project 8 + viva 3; keep tested, commented programs for every practical-list item and be able to explain each line.

Ends with a 14-question checkpoint (80% passes) and a mini project: Student Result Management System.