.size()

The .size() method returns the number of elements in the vector. It follows the consistency of other standard library containers, such as maps and strings.

Syntax

vector.size();

The vector must be defined using std::vector before the .size() method can be used.

Example

In the example below, .size() is called on the numbers vector:

#include <iostream>
#include <vector>

int main() {
    // Declaring a vector with 4 integers
    std::vector<int> numbers = {1, 2, 3, 4};

    // Print out vector size
    std::cout << numbers.size();
}

The output of the above code is:

4