输入：Map = { ABC = 10, DEF = 30, XYZ = 20 }
输出：DEF = 30

输入：Map = { 1 = 40, 2 = 30, 3 = 60 }
输出：3 = 60

map::iterator itr;
for (itr = some_map.begin();
     itr != some_map.end();
     ++itr) 
{
    //操作
}

// C++程序：在Map中查找具有最大值的条目
 
#include 
using namespace std;
 
//函数：打印Map
void printMap(map sampleMap)
{
    map::iterator itr;
    for (itr = sampleMap.begin();
        itr != sampleMap.end();
        ++itr) {
        cout << itr->first
            << " = " << itr->second << ", ";
    }
    cout << endl;
}
 
//函数：查找具有最大值的Entry
pair findEntryWithLargestValue(
    map sampleMap)
{
 
    // 引用变量变量，有助于查找具有最高值的Entry
    pair entryWithMaxValue
        = make_pair(0, 0);
 
    //在Map中进行迭代，以查找所需的条目
    map::iterator currentEntry;
    for (currentEntry = sampleMap.begin();
        currentEntry != sampleMap.end();
        ++currentEntry) {
 
        //如果这个条目的值比最大值更高，则将这个条目设置为最大值
        if (currentEntry->second
            > entryWithMaxValue.second) {
 
            entryWithMaxValue
                = make_pair(
                    currentEntry->first,
                    currentEntry->second);
        }
    }
 
    return entryWithMaxValue;
}
 
//驱动程序
int main()
{
 
    // Map
    map sampleMap;
    sampleMap.insert(pair(1, 40));
    sampleMap.insert(pair(2, 30));
    sampleMap.insert(pair(3, 60));
 
    //输出Map
    cout << "Map: ";
    printMap(sampleMap);
 
    //获取具有最大值的条目
    pair entryWithMaxValue
        = findEntryWithLargestValue(sampleMap);
 
    //打印条目
    cout << "Entry with highest value: "
        << entryWithMaxValue.first << " = "
        << entryWithMaxValue.second << endl;
 
    return 0;
}  

Map: 1 = 40, 2 = 30, 3 = 60, 
Entry with highest value: 3 = 60