unordered_set::count
Finds the number of elements matching a specified key.
size_type count(const Key& keyval) const;
Parameters
- keyval
Key value to search for.
Remarks
The member function returns the number of elements in the range delimited by unordered_set::equal_range(keyval).
Example
// std_tr1__unordered_set__unordered_set_count.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;
std::cout << "count('A') == " << c1.count('A') << std::endl;
std::cout << "count('b') == " << c1.count('b') << std::endl;
std::cout << "count('C') == " << c1.count('C') << std::endl;
return (0);
}
[c] [b] [a]
count('A') == 0
count('b') == 1
count('C') == 0
Requirements
Header: <unordered_set>
Namespace: std