Home - News ( United States | United Kingdom | Italy | Germany ) - Football scores

Showing content from http://en.cppreference.com/w/cpp/language/attributes/../../container/unordered_map/empty.html below:

std::unordered_map<Key,T,Hash,KeyEqual,Allocator>::empty - cppreference.com

bool empty() const noexcept;

Checks if the container has no elements.

true if the container is empty, false otherwise.

Constant.

The following code uses empty to check if a std::unordered_map<int, int> contains any elements:

#include <iostream>
#include <unordered_map>
#include <utility>
 
int main()
{
    std::unordered_map<int,int> numbers;
    std::cout << std::boolalpha;
    std::cout << "Initially, numbers.empty(): " << numbers.empty() << '\n';
 
    numbers.emplace(42, 13);
    numbers.insert(std::make_pair(13317, 123));
    std::cout << "After adding elements, numbers.empty(): " << numbers.empty() << '\n';
}

Output:

Initially, numbers.empty(): true
After adding elements, numbers.empty(): false

RetroSearch is an open source project built by @garambo | Open a GitHub Issue

Search and Browse the WWW like it's 1997 | Search results from DuckDuckGo

HTML: 3.2 | Encoding: UTF-8 | Version: 0.7.4