map1.cpp

来自「stl自带源码」· C++ 代码 · 共 65 行

/* 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 <map>
#include <string>
using namespace std;

int main()
{
    /* create map / associative array
     * - keys are strings
     * - values are floats
     */
    typedef map<string,float> StringFloatMap;

    StringFloatMap stocks;      // create empty container

    // insert some elements
    stocks["BASF"] = 369.50;
    stocks["VW"] = 413.50;
    stocks["Daimler"] = 819.00;
    stocks["BMW"] = 834.00;
    stocks["Siemens"] = 842.20;

    // print all elements
    StringFloatMap::iterator pos;
    for (pos = stocks.begin(); pos != stocks.end(); ++pos) {
        cout << "stock: " << pos->first << "\t"
             << "price: " << pos->second << endl;
    }
    cout << endl;

    // boom (all prices doubled)
    for (pos = stocks.begin(); pos != stocks.end(); ++pos) {
        pos->second *= 2;
    }

    // print all elements
    for (pos = stocks.begin(); pos != stocks.end(); ++pos) {
        cout << "stock: " << pos->first << "\t"
             << "price: " << pos->second << endl;
    }
    cout << endl;

    /* rename key from "VW" to "Volkswagen"
     * - only provided by exchanging element
     */
    stocks["Volkswagen"] = stocks["VW"];
    stocks.erase("VW");

    // print all elements
    for (pos = stocks.begin(); pos != stocks.end(); ++pos) {
        cout << "stock: " << pos->first << "\t"
             << "price: " << pos->second << endl;
    }
}