vimwiki

C++ vector

Vector are similar to arrays but can dynamically change size.

Create a Vector

Include the vector library and create a vector with:

std::vector<type> <name>;

#include <vector>

std::vector<char> alphabet;
// or
std::vector<char> alphabet = {'a', 'b', 'c'};

Note: the type cannot be changed after its declaration.

Vector methods

Add elements

Add element at the end of a vector with .push_back()

std::vector<int> my_numbers;
my_numbers.push_back(2);
my_numbers.push_back(6);

// my_numbers contains {2, 6}

Remove elements

Remove the last element with .pop_back().

my_numbers.pop_back();

Accessing elements

Access a given index with brackets []

std::cout << my_numbers[2];

Access the first and last and first element with .front() and .back()

std::cout << my_numbers.front();
std::cout << my_numbers.back();

Vector size

Get the number of elements with .size()

std::vector<std::string> colors = {"Red", "Green", "Blue"};

std::cout << colors.size(); // outputs: 3

.empty() return 0 if a vector is empty and 1 otherwise.

Iterating over a vector

Use for loop (with vector.size()) or a for-each loop.