C++如何删除map容器中指定值的元素详解

//插入val到pos的后面，然后返回一个指向这个元素的迭代器
iterator insert( iterator pos, const pair<KEY_TYPE,VALUE_TYPE> &val );
//插入start到end的元素到map中
void insert( input_iterator start, input_iterator end );
//只有在val不存在时插入val。返回值是一个指向被插入元素的迭代器和一个描述是否插入的bool值
pair<iterator, bool> insert( const pair<KEY_TYPE,VALUE_TYPE> &val );

//erase()函数删除在pos位置的元素，或者删除在start和end之间的元素，或者删除那些值为key的所有元素
void erase( iterator pos );
void erase( iterator start, iterator end );
size_type erase( const KEY_TYPE &key );

/**
 * @FileName map_del_str.cpp
 * @Describe A simple example for deleting an element of string in map.
 * @Author  vfhky 2016-06-26 10:26 https://typecodes.com/cseries/mapdelintstring.html
 * @Compile  g++ map_del_str.cpp -o map_del_str
 * @Reference 
 */
#include <iostream>
#include <map>

using namespace std;
#define TOTAL 10
#define DEL_STR "123"


/**
 * 删除map中所有元素为str的数据
 */
void fun( map<int, string *> &map1, const string str )
{
 map<int, string *>::iterator it;
 int i_Total = 0;
 for( it=map1.begin(); it!=map1.end(); )
 {
  if( *(it->second) == str )
  {
   /**
    * 123 123 123 123 123 123 123 123 123 123 
    */
   cout << *(it->second) << " ";

   //一定要先释放内存的控制
   delete it->second;
   it->second = NULL;

   //再删除迭代
   map1.erase(it++);
   ++i_Total;
  }
  else
  {
   it++;
  }
 }

 //i_Total=[10]
 cout << endl << "i_Total=[" << i_Total << "]" << endl;
}

int main( int argc, char **argv )
{
 map<int, string *> map1;

 //初始化map1
 for( int i=0; i<TOTAL; i++ )
 {
  map1.insert( pair<int, string *>(i,new string("123")) );
  //map1[i] = new string("123");
 }

 //删除为DEL_STR的元素
 fun( map1, DEL_STR );

 //查看最后的数据
 map<int, string *>::iterator it1;
 for( it1=map1.begin(); it1!=map1.end(); ++it1 )
 {
  cout << "map1[" << it1->first << "]=[" << *(it1->second) << "]" << endl;
 }
 return 0;
}

/**
 * @FileName map_del_int.cpp
 * @Describe A simple example for deleting an element of interger in map.
 * @Author  vfhky 2016-06-26 10:26 https://typecodes.com/cseries/mapdelintstring.html
 * @Compile  g++ map_del_int.cpp -o map_del_int
 * @Reference 
 */
#include <iostream>
#include <map>

using namespace std;
#define TOTAL 100
#define DEL_INT 3


/**
 * 删除map中所有值整除NUM的元素
 */
void fun( map<int,int> &map1, const int NUM )
{
 map<int, int>::iterator it;
 int i_Total = 0;
 for( it=map1.begin(); it!=map1.end(); )
 {
  if( it->second % NUM == 0 )
  {
   /**
    * 0 3 6 9 12 15 18 21 24 27 30 33 36 39 42 45 48 51 54 57 60 63 66 69 72 75 78 81 84 87 90 93 96 99 
    */
   cout << it->second << " ";
   map1.erase(it++);
   ++i_Total;
  }
  else
  {
   it++;
  }
 }
 cout << endl << "i_Total=[" << i_Total << "]" << endl;
}

int main( int argc, char **argv )
{
 map<int, int> map1;

 //初始化map1
 for( int i=0; i<TOTAL; i++ )
 {
  map1.insert(pair<int, int>(i,i));
  //map1[i] = i;
 }

 //删除整除3的元素
 fun( map1, DEL_INT );

 //查看最后的数据
 map<int, int>::iterator it1;
 for( it1=map1.begin(); it1!=map1.end(); ++it1 )
 {
  cout << "map1[" << it1->first << "]=[" << it1->second << "]" << endl;
 }
 return 0;
}