C++ STL (Vectors, Maps, Sets)

What is STL?

The Standard Template Library (STL) provides built-in data structures and algorithms.

It helps you write efficient and clean code.

Vector (Dynamic Array)

A vector is a dynamic array that can change size.

Map (Key-Value Pairs)

A map stores key-value pairs sorted by key.

Set (Unique Values)

A set stores unique values and automatically sorts them.

Full Example

Why STL is Important

• Speeds up development
• Reduces errors
• Used in interviews

Common Mistakes

• Forgetting #include
• Confusing map vs set
• Misusing vector indexing

Practice

Create a vector, map, and set. Insert values and print them.

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