unordered_set::size

發行項
02/28/2013

計數項目的數目。

size_type size() const;

備註

成員函式會傳回受控制序列的長度。

範例

// std_tr1__unordered_set__unordered_set_size.cpp 
// compile with: /EHsc 
#include <unordered_set> 
#include <iostream> 
 
typedef std::unordered_set<char> Myset; 
int main() 
    { 
    Myset c1; 
 
    c1.insert('a'); 
    c1.insert('b'); 
    c1.insert('c'); 
 
// display contents " [c] [b] [a]" 
    for (Myset::const_iterator it = c1.begin(); 
        it != c1.end(); ++it) 
        std::cout << " [" << *it << "]"; 
    std::cout << std::endl; 
 
// clear the container and reinspect 
    c1.clear(); 
    std::cout << "size == " << c1.size() << std::endl; 
    std::cout << "empty() == " << std::boolalpha << c1.empty() << std::endl; 
    std::cout << std::endl; 
 
    c1.insert('d'); 
    c1.insert('e'); 
 
// display contents " [e] [d]" 
    for (Myset::const_iterator it = c1.begin(); 
        it != c1.end(); ++it) 
        std::cout << " [" << *it << "]"; 
    std::cout << std::endl; 
 
    std::cout << "size == " << c1.size() << std::endl; 
    std::cout << "empty() == " << std::boolalpha << c1.empty() << std::endl; 
 
    return (0); 
    }