What is defensive programming?
💡 Concept: Defensive Programming
Defensive programming is a proactive approach to writing code that anticipates and handles potential errors to increase software robustness.
📘 Quick Intro
It emphasizes writing code that checks inputs, validates assumptions, and fails gracefully.
🧠 Analogy
Like a pilot performing pre-flight checks to ensure a safe flight, preventing issues before they arise.
🔧 Technical Explanation
- Validate all inputs and parameters.
- Check for null references and unexpected values.
- Use exception handling to manage unforeseen errors.
- Write unit tests to verify expected behaviors.
- Implement logging for monitoring and diagnostics.
🎯 Use Cases
- ✅ Developing mission-critical systems.
- ✅ Writing reusable and maintainable libraries.
- ✅ Creating user input validation logic.
- ✅ Designing fault-tolerant applications.
💻 Code Example
public int Divide(int numerator, int denominator) {
if (denominator == 0) {
throw new ArgumentException(""Denominator cannot be zero."");
}
return numerator / denominator;
}
❓ Interview Q&A
Q1: What is defensive programming?
A: Writing code to anticipate and handle errors.
Q2: Why validate inputs?
A: To avoid runtime errors and invalid states.
Q3: How does it improve software?
A: Increases reliability and maintainability.
Q4: What role do exceptions play?
A: Manage unexpected conditions gracefully.
Q5: Should you test defensive code?
A: Yes, with unit tests.
Q6: Is defensive programming costly?
A: Slight overhead but worth the reliability.
Q7: Can logging help?
A: Yes, for diagnostics.
Q8: Does it replace good design?
A: No, complements it.
Q9: Is it only for critical apps?
A: Useful for all apps.
Q10: What tools assist defensive programming?
A: Static analyzers and testing frameworks.
📝 MCQs
Q1. What is defensive programming?
- Writing error-resistant code
- Writing fast code
- Ignoring errors
- Logging only
Q2. Why validate inputs?
- Improve speed
- Avoid runtime errors
- Skip validation
- Reduce logging
Q3. How does it improve software?
- Performance
- Reliability
- Security
- Speed
Q4. What role do exceptions play?
- Ignore errors
- Handle unexpected errors
- Create errors
- Log errors only
Q5. Should you test defensive code?
- No
- Yes
- Sometimes
- Rarely
Q6. Is defensive programming costly?
- No cost
- High cost
- Slight overhead
- No overhead
Q7. Can logging help?
- No
- Yes
- Sometimes
- Never
Q8. Does it replace good design?
- Yes
- No
- Sometimes
- Rarely
Q9. Is it only for critical apps?
- Yes
- No
- Sometimes
- Rarely
Q10. What tools assist defensive programming?
- Static analyzers
- Compilers
- Profilers
- Decompilers
💡 Bonus Insight
Defensive programming is a key practice to build resilient and maintainable software.
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