Implement zero mover algorithm to shift all zeros to the end of array

[janvi100104]

Summary by Sourcery

Implement an in-place algorithm to shift all zeros in an array to its end in O(n) time and provide a CLI with a demo fallback for usage.

New Features:

• Introduce moveZerosToEnd method to relocate zeros to the end of an integer array in-place.
• Add main method to handle command-line input or run a demo fallback and print the resulting array.

[sourcery-ai]

Reviewer's Guide

Introduces zeroInTheEnd.java with an in-place, O(n)/O(1) algorithm to move zeros to the end of an array and a main method handling input parsing, demo fallback, validation, and formatted output.

Sequence diagram for main method input handling and zero moving

sequenceDiagram
actor User
participant "zeroInTheEnd.main()"
participant "Scanner"
participant "moveZerosToEnd()"
User->>"zeroInTheEnd.main()": Start program
"zeroInTheEnd.main()"->>"Scanner": Read input
alt No input detected
    "zeroInTheEnd.main()"->>"moveZerosToEnd()": Call with demo array
    "moveZerosToEnd()"-->>"zeroInTheEnd.main()": Demo array modified
    "zeroInTheEnd.main()"->>User: Print demo result
else Input detected
    "zeroInTheEnd.main()"->>"Scanner": Read n
    "zeroInTheEnd.main()"->>"Scanner": Read n integers
    "zeroInTheEnd.main()"->>"moveZerosToEnd()": Call with user array
    "moveZerosToEnd()"-->>"zeroInTheEnd.main()": User array modified
    "zeroInTheEnd.main()"->>User: Print result
end

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Class diagram for zeroInTheEnd.java

classDiagram
class zeroInTheEnd {
  +moveZerosToEnd(int[] a)
  +main(String[] args)
}

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File-Level Changes

Change	Details	Files
Implement zero-to-end algorithm using two pointers	Maintain read and write indices to shift non-zero values forward After processing, fill remaining slots with zeros Include JavaDoc specifying O(n) time and O(1) space	Java/zeroInTheEnd.java
Add main method for CLI input, demo fallback, and output formatting	Detect missing input to run demo scenario Read array length and elements with validation for insufficient data Assemble output via StringJoiner for space-separated printing Ensure Scanner is closed in a finally block	Java/zeroInTheEnd.java

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📥 Commits

Reviewing files that changed from the base of the PR and between 220d1e0 and fc858c4.

📒 Files selected for processing (1)

• Java/zeroInTheEnd.java (1 hunks)

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[qodo-code-review]

PR Compliance Guide 🔍

Below is a summary of compliance checks for this PR:

Security Compliance
⚪	Resource handling risk Description: The Scanner used for reading from System.in is closed in a finally block, which can inadvertently close the underlying System.in stream for the entire JVM process if this code runs within a larger application; prefer not closing System.in or scoping the scanner to avoid side effects. zeroInTheEnd.java [24-57] Referred Code public static void main(String[] args) { Scanner sc = new Scanner(System.in); try { if (!sc.hasNextInt()) { // Demo fallback int[] demo = {0, 1, 0, 3, 12, 0, 5}; System.out.println("No input detected — running demo: " + Arrays.toString(demo)); moveZerosToEnd(demo); System.out.println(Arrays.toString(demo)); return; } int n = sc.nextInt(); int[] a = new int[n]; for (int i = 0; i < n; i++) { if (!sc.hasNextInt()) { System.err.println("Expected " + n + " integers but got fewer."); return; } a[i] = sc.nextInt(); } ... (clipped 13 lines)
Ticket Compliance
⚪	🎫 No ticket provided Create ticket/issue
Codebase Duplication Compliance
⚪	Codebase context is not defined Follow the guide to enable codebase context checks.
Custom Compliance
🟢	Generic: Secure Error Handling Objective: To prevent the leakage of sensitive system information through error messages while providing sufficient detail for internal debugging. Status: Passed
	Generic: Secure Logging Practices Objective: To ensure logs are useful for debugging and auditing without exposing sensitive information like PII, PHI, or cardholder data. Status: Passed
🔴	Generic: Meaningful Naming and Self-Documenting Code Objective: Ensure all identifiers clearly express their purpose and intent, making code self-documenting Status: Class naming: Class name zeroInTheEnd does not follow Java naming conventions (should be PascalCase like ZeroInTheEnd) reducing self-documentation quality. Referred Code public class zeroInTheEnd {
⚪	Generic: Comprehensive Audit Trails Objective: To create a detailed and reliable record of critical system actions for security analysis and compliance. Status: No audit logs: The program performs input processing and array mutation without emitting any audit logs, but it is unclear whether audit trails are required for this non-critical utility. Referred Code public static void main(String[] args) { Scanner sc = new Scanner(System.in); try { if (!sc.hasNextInt()) { // Demo fallback int[] demo = {0, 1, 0, 3, 12, 0, 5}; System.out.println("No input detected — running demo: " + Arrays.toString(demo)); moveZerosToEnd(demo); System.out.println(Arrays.toString(demo)); return; } int n = sc.nextInt(); int[] a = new int[n]; for (int i = 0; i < n; i++) { if (!sc.hasNextInt()) { System.err.println("Expected " + n + " integers but got fewer."); return; } a[i] = sc.nextInt(); } ... (clipped 10 lines)
	Generic: Robust Error Handling and Edge Case Management Objective: Ensure comprehensive error handling that provides meaningful context and graceful degradation Status: Input edge cases: The code does not validate negative n or excessively large sizes and provides limited context in error messages, which may be acceptable for a demo CLI but lacks robust handling. Referred Code int n = sc.nextInt(); int[] a = new int[n]; for (int i = 0; i < n; i++) { if (!sc.hasNextInt()) { System.err.println("Expected " + n + " integers but got fewer."); return; } a[i] = sc.nextInt(); }
	Generic: Security-First Input Validation and Data Handling Objective: Ensure all data inputs are validated, sanitized, and handled securely to prevent vulnerabilities Status: Size validation: External input n from Scanner is used to allocate an array without validation (e.g., negative or huge values), which could lead to runtime errors or resource issues. Referred Code int n = sc.nextInt(); int[] a = new int[n]; for (int i = 0; i < n; i++) {

Compliance status legend

🟢 - Fully Compliant
🟡 - Partial Compliant
🔴 - Not Compliant
⚪ - Requires Further Human Verification
🏷️ - Compliance label

[sourcery-ai]

Hey there - I've reviewed your changes - here's some feedback:

• Rename the class to follow Java naming conventions (e.g., ZeroInTheEnd or ZeroMover) for clarity.
• Consider extracting the demo and input-handling logic into separate methods or classes to keep the core algorithm focused and easier to test.

Prompt for AI Agents

Please address the comments from this code review:

## Overall Comments
- Rename the class to follow Java naming conventions (e.g., ZeroInTheEnd or ZeroMover) for clarity.
- Consider extracting the demo and input-handling logic into separate methods or classes to keep the core algorithm focused and easier to test.

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[qodo-code-review]

PR Code Suggestions ✨

Explore these optional code suggestions:

Category	Suggestion	Impact
Possible issue	Add validation for negative array size Add a check to ensure the user-provided array size n is non-negative, preventing a potential NegativeArraySizeException. Java/zeroInTheEnd.java [36-37] int n = sc.nextInt(); +if (n < 0) { + System.err.println("Array size cannot be negative."); + return; +} int[] a = new int[n]; Apply / Chat Suggestion importance[1-10]: 7 __ Why: The suggestion correctly identifies that a negative input for array size n will cause a NegativeArraySizeException, and the proposed fix improves the program's robustness by handling this edge case.	Medium
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