What are generics in C#?
💡 Concept: Generics in C#
Generics allow you to define classes, methods, and data structures with placeholders for the type of data they store or use.
📘 Quick Intro
Generics increase type safety and reduce the need for casting by allowing types to be specified at compile time.
🧠 Analogy
Think of generics like templates for containers that can hold any type, ensuring safety and reusability.
🔧 Technical Explanation
- ⚙️ Generics are declared with angle brackets <T> representing type parameters.
- 📚 Enable code reuse for multiple data types.
- 🔒 Provide compile-time type safety.
- 🚀 Improve performance by avoiding boxing/unboxing.
- 🛠️ Used in collections like List<T>, Dictionary<TKey, TValue>, etc.
🎯 Use Cases
- ✅ Creating reusable data structures.
- ✅ Writing type-safe algorithms.
- ✅ Avoiding runtime type errors.
- ✅ Enhancing performance in collections.
💻 Code Example
using System;
using System.Collections.Generic;
class Program {
static void Main() {
List<string> names = new List<string>();
names.Add(""Alice"");
names.Add(""Bob"");
foreach (var name in names) {
Console.WriteLine(name);
}
}
}
❓ Interview Q&A
Q1: What are generics?
A: Templates for types to enable code reuse.
Q2: How do generics improve type safety?
A: Types are checked at compile time.
Q3: What problem do generics solve?
A: Avoids casting and runtime errors.
Q4: Name some generic collections.
A: List<T>, Dictionary<TKey, TValue>.
Q5: Can generics improve performance?
A: Yes, by avoiding boxing/unboxing.
Q6: What symbol is used for generics?
A: Angle brackets <>.
Q7: Are generics limited to classes?
A: No, methods and interfaces can be generic.
Q8: Can generics be constrained?
A: Yes, with constraints like where T : class.
Q9: What is type parameter?
A: A placeholder type in generic declarations.
Q10: Can you create generic delegates?
A: Yes.
📝 MCQs
Q1. What are generics?
- Specific types
- Templates for types
- Variables
- Constants
Q2. How do generics improve type safety?
- Runtime checking
- Compile-time checking
- No checking
- None
Q3. What problem do generics solve?
- Type inference
- Avoid casting
- Serialization
- Reflection
Q4. Name generic collections.
- ArrayList
- List<T>, Dictionary<TKey, TValue>
- Hashtable
- Queue
Q5. Can generics improve performance?
- No
- Yes
- Sometimes
- Never
Q6. Symbol for generics?
- Curly braces {}
- Parentheses ()
- Angle brackets <>
- Square brackets []
Q7. Are generics limited to classes?
- Yes
- No
- Only structs
- Only interfaces
Q8. Can generics be constrained?
- No
- Yes
- Sometimes
- Never
Q9. What is type parameter?
- Concrete type
- Placeholder type
- Instance
- Variable
Q10. Can you create generic delegates?
- No
- Yes
- Sometimes
- Always
💡 Bonus Insight
Generics enable writing flexible, reusable, and efficient code in C# by abstracting over data types.
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