stl map容器中指针的释放

最新推荐文章于 2023-11-09 13:25:19 发布

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本文演示了如何使用C++ STL中的map容器存储自定义结构体的指针，并展示了插入、查找、修改、删除等基本操作。同时，还介绍了如何避免内存泄漏。

struct MyStruct
{
   int i;
   char c;

   MyStruct(int i, char c)
   {
       this->i = i;
       this->c = c;
   }
};

int stl_ptr_test()
{
   MyStruct* pst1 = new MyStruct(1, 'a');
   MyStruct* pst2 = new MyStruct(1, 'a');
   MyStruct* pst3 = new MyStruct(3, 'c');

   map<int, MyStruct*> map1; // 其中的value为指针型的

   map1.insert(pair<int, MyStruct*>(10, pst1));
   map1.insert(pair<int, MyStruct*>(11, pst2));
   map1.insert(pair<int, MyStruct*>(12, pst3));

   map<int, MyStruct*>::iterator iter = map1.find(11);
   cout << iter->second->i << ' ' << iter->second->c << endl;

   MyStruct* pst = iter->second;
   pst->c = 'b';

   iter = map1.find(11);
   cout << iter->second->i << ' ' << iter->second->c << endl;

   iter = map1.find(10);
   delete iter->second; // 释放指针
   map1.erase(10); // 从map中删除元素

   iter = map1.find(10);
   if (iter == map1.end())
   {
       cout << "not found" << endl;
   }
   else
   {
       cout << "found: " << iter->second->i << ' ' << iter->second->c << endl;
   }

   for (iter = map1.begin(); iter != map1.end();)
   {
       cout << iter->second->i << " " << iter->second->c << endl;

       delete iter->second; // 释放指针
       map1.erase(iter++); // 从map中删除元素，注意iter++的写法
   }

   map1.clear();

   return 0;
}