#include<iostream>
#include<map>
using namespace std;

/*
 * maps are used to store 1:1 relationships
 * they are really sets with a pair
 * they are not random access, but the []
 * means key indexing
 */

// overloading the output stream operator
ostream & operator << ( ostream & ost, const map<int,float> & l )
{
    map<int,float>::const_iterator i = l.begin();
    for ( ; i != l.end() ; ++i )
        ost << i->first << ":" << i->second << endl;
    return ost;
}

int main()
{
    map< int, float > m;

    for ( int i = 0 ; i < 10 ; ++i )
        m.insert( make_pair( i, i * 1.01 ) );
    cout << m << endl;

    // add some more
    for ( int i = 20 ; i < 30 ; ++i )
        m[i] = i * 1.01;
    cout << m << endl;

    // show what value matches key 7
    cout << m[7] << endl;
    // this overwrites the existing value
    m[7] = 17.888;
    // this adds a new key/value pair
    m[19] = 86.86;
    cout << m << endl;

    return 0;
}