exercise 1 done

[Keerthi0910]

No description provided.

[super30admin]

The student has provided two implementations of a stack: one using an array (Exercise_1.java) and one using a linked list (Exercise_2.java). Let me evaluate both.

Exercise_1.java (Array-based Stack):

• Correctness: The implementation is mostly correct. The push, pop, and peek operations work as expected.
• Issues:
  • throw new Error("...") is not ideal. Should use throw new RuntimeException("...") or a custom exception.
  • The isEmpty() method is defined but never used in the main method.
  • The MAX constant is hardcoded to 1000, which limits flexibility.
• Time Complexity: O(1) for all operations - correct.
• Space Complexity: O(n) - correct.

Exercise_2.java (Linked List-based Stack):

• Correctness: There are syntax errors and missing braces.
• Issues:
  • this data = data; should be this.data = data; (syntax error)
  • The peek() method is missing a closing brace and the return 0; statement for the empty case.
  • The class is missing a closing brace at the end.
  • The main method is inside the peek() method due to missing braces.
  • StackNode should be a non-static inner class or properly structured.
• Time Complexity: O(1) for all operations - correct.
• Space Complexity: O(n) - correct.

General Code Quality Issues:

• Inconsistent error handling (some methods throw exceptions, others return 0).
• Missing JavaDoc comments.
• The isEmpty() method in Exercise_1 is unused.
• No input validation or testing of edge cases.