THINK++ — Engineering Visualized

Dynamic Array

STL Vector

A std::vector is a dynamic array that can grow and shrink in size automatically. It's the most used container in modern C++.

BASIC USAGE

#include <vector>
vector<int> v = {1, 2, 3};

v.push_back(4); // Adds 4 to end
v.pop_back();  // Removes last element

cout << v.size(); // 3
cout << v[0];     // Access like array

CONTIGUOUS

Elements are stored in contiguous memory, ensuring O(1) random access.

AMORTIZED O(1)

Inserting at the end (push_back) is very efficient on average.

CAPACITY VS SIZE

Size is the current number of elements. Capacity is the total space allocated. Vectors often allocate more memory than they need to avoid constant reallocations.

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