C++ STL map详解-优快云博客

本文链接：https://blog.youkuaiyun.com/ffmemcpy/article/details/107344520

本文深入探讨了C++ STL中map容器的使用方法，包括不同构造函数的应用、元素的插入与删除、查找操作以及迭代器的运用。通过具体示例展示了如何创建、操作和遍历map，为读者提供了全面的map使用指南。

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   //构造函数
   //map()
   map<char, int> m1;

   //指定一个比较函数来创建map对象
   struct KeyCompare
   {
       bool operator()(const char* s1, const char* s2) const
       {
           return strcmp(s1, s2) < 0;
       }
   };
   map<const char*, int, KeyCompare> m2;

//map(const _Myt& _Right)
map<const char*, int, KeyCompare> m3(m2);

   //map(_Iter _First, _Iter _Last)
   pair<int, char> p1(1, 'a');
   pair<int, char> p2(2, 'b');
   pair<int, char> p3(3, 'c');
   pair<int, char> arr[] = { p1, p2, p3 };
   map<int, char> m4(arr, arr + 3);

   //插入元素
   pair<map<int, char>::iterator, bool> bRet = m4.insert(make_pair(4, 'd'));
   if (bRet.second)
   {
       cout << "insert success" << endl;
   }
   else
   {
       cout << "insert failed" << endl;
   }

   //在可能的位置之前插入元素
   pair<int, char> p5(5, 'e');
   map<int, char>::iterator i = m4.insert(m4.begin(), p5);

   //插入区间元素
   map<int, char> m5;
   m5.insert(m4.begin(), m4.end());
   map<int, char>::iterator iter;
   for (iter = m5.begin(); iter != m5.end(); ++iter)
   {
       cout << iter->first << " " << iter->second << endl;
   }
   cout << endl;
   //1 a
   //2 b
   //3 c
   //4 d
   //5 e
   map<int, char>::reverse_iterator rIter;
   for (rIter = m5.rbegin(); rIter != m5.rend(); ++rIter)
   {
       cout << rIter->first << " " << rIter->second << endl;
   }
   cout << endl;

   map<int, char>::iterator rFind = m5.find(3);
   if (rFind == m5.end())
   {
       cout << "not found" << endl;
   }
   else
   {
       int i = 0;
       iter = m5.begin();
       while (iter != rFind)
       {
           ++i;
           ++iter;
       }
       cout << "find index:" << i << endl;
   }