size_type size() const; | (since C++11) |
Returns the number of elements in the container, i.e. std::distance(begin(), end()).
Parameters
(none).
Return value
The number of elements in the container.
Exceptions
noexcept specification: noexceptComplexity
Constant.
Example
The following code uses size to display the number of elements in a std::unordered_map:
#include <unordered_map>
#include <iostream>
int main()
{
std::unordered_map<int,char> nums {{1, 'a'}, {3, 'b'}, {5, 'c'}, {7, 'd'}};
std::cout << "nums contains " << nums.size() << " elements.\n";
}Output:
nums contains 4 elements.
See also
| checks whether the container is empty (public member function) | |
| returns the maximum possible number of elements (public member function) |
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