set::count

set::count

set::count

Visual Studio .NET 2003

其他版本

Returns the number of elements in a set whose key matches a parameter-specified key.

size_type count( const Key& _Key ) const;

Parameter

_Key

The key of the elements to be matched from the set.

Return Value

1 if the set contains an element whose sort key matches the parameter key. 0 if the set does not contain an element with a matching key.

Remarks

The member function returns the number of elements in the following range:

[lower_bound (_Key ), upper_bound (_Key ) ).

Example

// set_count.cpp// compile with: /EHsc #include #include int main( ) { using namespace std; set s1; int i; s1.insert( 1 ); s1.insert( 1 ); // Keys must be unique in set, so duplicates are ignored i = s1.count( 1 ); cout << "The number of elements in s1 with a sort key of 1 is: " << i << "." << endl; i = s1.count( 2 ); cout << "The number of elements in s1 with a sort key of 2 is: " << i << "." << endl; }

Output

The number of elements in s1 with a sort key of 1 is: 1.The number of elements in s1 with a sort key of 2 is: 0.

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