Mega Code Archive
Map find demo
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/* The following code example is taken from the book
* "The C++ Standard Library - A Tutorial and Reference"
* by Nicolai M. Josuttis, Addison-Wesley, 1999
*
* (C) Copyright Nicolai M. Josuttis 1999.
* Permission to copy, use, modify, sell and distribute this software
* is granted provided this copyright notice appears in all copies.
* This software is provided "as is" without express or implied
* warranty, and with no claim as to its suitability for any purpose.
*/
#include <iostream>
#include <algorithm>
#include <map>
using namespace std;
/* function object to check the value of a map element
*/
template <class K, class V>
class value_equals {
private:
V value;
public:
// constructor (initialize value to compare with)
value_equals (const V& v)
: value(v) {
}
// comparison
bool operator() (pair<const K, V> elem) {
return elem.second == value;
}
};
int main()
{
typedef map<float,float> FloatFloatMap;
FloatFloatMap coll;
FloatFloatMap::iterator pos;
// fill container
coll[1]=7;
coll[2]=4;
coll[3]=2;
coll[4]=3;
coll[5]=6;
coll[6]=1;
coll[7]=3;
// search an element with key 3.0
pos = coll.find(3.0); // logarithmic complexity
if (pos != coll.end()) {
cout << pos->first << ": "
<< pos->second << endl;
}
}
3: 2
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