# Vectors

In C++, a vector is a dynamic list of items, that can shrink and grow in size. It is created using std::vector<type> name; and it can only store values of the same type.

To use vectors, it is necessary to #include the vector library

#include <iostream>
#include <vector>

int main() {

}


During the creation of a C++ vector, the data type of its elements must be specified. Once the vector is created, the type cannot be changed.

## Index

An index refers to an element’s position within an ordered list, like a vector or an array. The first element has an index of 0.

A specific element in a vector or an array can be accessed using its index, like name[index].

std::vector<int> grades = {65, 78, 90, 85}

// Outputs: 90


## Vector Sizes

The .size() function can be used to return the number of elements in a vector, like name.size().

std::vector<std::string> employees;

employees.push_back("michael");
employees.push_back("jim");
employees.push_back("pam");
employees.push_back("dwight");

std::cout << employees.size();
// Prints: 4


## Push and Pop

The following functions can be used to add and remove an element in a vector:

• .push_back() to add an element to the “end” of a vector
• .pop_back() to remove an element from the “end” of a vector
std::vector<std::string> wishlist;

wishlist.push_back("GTX 3090");
wishlist.push_back("Ryzen 5 5600");

wishlist.pop_back();

std::cout << wishlist.size();
// Prints: 1