STL之map容器和multimap容器

  1 #include <iostream>
  2 #include<map>
  3 #include <algorithm>
  4 
  5 using namespace std;
  6 
  7 void test01() {
  8     map<int, int>m;  //注意和其他容器相区分，一个是序号另外一个是键值
  9     m.insert(pair<int,int>(1,10));  //这里运用四种方法给map容器插值
 10     m.insert(make_pair(2,20));
 11     m.insert(map<int,int>::value_type(3,30));
 12     m[4] = 40;
 13 
 14     for (map<int,int>::iterator it=m.begin();it!=m.end();it++)
 15     {
 16         cout << it->first << "  " << (*it).second << endl;
 17     }
 18 
 19     if(m.empty())
 20     {
 21         cout << "空" << endl;
 22     }
 23     else
 24     {
 25     cout << "size = " << m.size() << endl;
 26     }
 27 }
 28 
 29 void test02() {
 30     map<int, int> m;
 31     m.insert(pair<int, int>(1, 10));
 32     m.insert(make_pair(2, 20));
 33     m.insert(map<int, int>::value_type(3, 30));
 34     m[4] = 40;
 35 
 36     m.erase(1);  //直接将第一个值删除
 37     for (map<int, int>::iterator it = m.begin(); it != m.end(); it++)
 38     {
 39         cout << "key = " << it->first << " value" << it->second << endl;
 40     }
 41 
 42     map<int, int>::iterator pos = m.find(2); //查找
 43     if (pos != m.end())
 44     {
 45         cout << "找到：key" << pos->first << " value:" << pos->second << endl;
 46     }
 47     else
 48     {
 49         cout << "未找到" << endl;
 50     }
 51 
 52     int num = m.count(3); //map的count 要么0 要么1 
 53     cout << "num = " << num << endl;
 54 
 55     // lower_bound(keyElem);//返回第一个key>=keyElem元素的迭代器。
 56 
 57     map<int, int>::iterator ret = m.lower_bound(3);
 58     if (ret != m.end())
 59     {
 60         cout << "lower_bound 中key" << ret->first << " value: " << ret->second << endl;
 61     }
 62     else
 63     {
 64         cout << "未找到" << endl;
 65     }
 66 
 67     //upper_bound(keyElem);//返回第一个key>keyElem元素的迭代器。
 68     ret = m.upper_bound(3);
 69     if (ret != m.end())
 70     {
 71         cout << "upper_bound 中key" << ret->first << " value: " << ret->second << endl;
 72     }
 73     else
 74     {
 75         cout << "未找到" << endl;
 76     }
 77 
 78     //equal_range(keyElem);//返回容器中key与keyElem相等的上下限的两个迭代器。
 79 
 80     pair<map<int, int>::iterator, map<int, int>::iterator> ret2 = m.equal_range(3);
 81 
 82     if (ret2.first != m.end())
 83     {
 84         cout << "找到了equal_range 中的lower_bound 的key " << ret2.first->first << " value: " << ret2.first->second << endl;
 85     }
 86     else
 87     {
 88         cout << "未找到" << endl;
 89     }
 90 
 91     if (ret2.second != m.end())
 92     {
 93         cout << "找到了equal_range 中的upper_bound 的key " << ret2.second->first << " value: " << ret2.second->second << endl;
 94     }
 95     else
 96     {
 97         cout << "未找到" << endl;
 98     }
 99 }
100 bool myCompare(int &v1, int &v2){
101         return v1 > v2;
102 }
103 
104 int main() {
105     //test01();
106     test02();
107     system("pause");
108     return 0;
109 }