C++ examples for STL:vector
The capacity of a vector is the number elements that it can store without allocating more memory.
The size of a vector is the number of elements it actually contains.
You can obtain the size and capacity of a vector by calling the size() or capacity() function.
These values are returned as integers of an unsigned integral type that is defined by your implementation. For example:
#include <iostream> #include <iomanip> #include <vector> using std::vector; int main()/*from www .ja v a 2 s. com*/ { std::vector<unsigned int> primes { 2u, 3u, 5u, 7u, 11u, 13u, 17u, 19u}; std::cout << "The size is " << primes.size() << std::endl; std::cout << "The capacity is " << primes.capacity() << std::endl; }
You can assign the size of the vector to an auto variable, for example:
auto nElements = primes.size(); // Store the number of elements