hash_map::at
Finds an element in a hash_map with a specified key value.
Type& at(
const Key& _Key
);
const Type& at(
const Key& _Key
) const;
Parameters
Parameter |
Description |
_Key |
The key value of the element that is to be found. |
Return Value
A reference to the data value of the element found.
Remarks
If the argument key value is not found, then the function throws an object of class out_of_range Class.
In Visual C++ .NET 2003, members of the <hash_map> and <hash_set> header files are no longer in the std namespace, but rather have been moved into the stdext namespace. See The stdext Namespace for more information.
Example
// hash_map_at.cpp
// compile with: /EHsc
#define _DEFINE_DEPRECATED_HASH_CLASSES 0
#include <hash_map>
#include <iostream>
int main( )
{
using namespace std;
using namespace stdext;
typedef pair <const int, int> cInt2Int;
hash_map <int, int> hm1;
// Insert data values
hm1.insert ( cInt2Int ( 1, 10 ) );
hm1.insert ( cInt2Int ( 2, 20 ) );
hm1.insert ( cInt2Int ( 3, 30 ) );
cout << "The values of the mapped elements are:";
for ( int i = 1 ; i <= hm1.size() ; i++ )
cout << " " << hm1.at(i);
cout << "." << endl;
}
Output
The values of the mapped elements are: 10 20 30.
Requirements
Header: <hash_map>
Namespace: stdext