C++ STL入门教程(7) multimap、multiset的使用

/*请务必运行以下程序后对照阅读*/ 
 
///头文件依旧是map 
#include <map> 
#include <string> 
#include <iostream> 
using namespace std; 
 
int main() 
{ 
  ///1. 初始化 
  multimap<int, string> mapStudent; 
  multimap<int, string>::iterator iter, beg, end; 
   
  ///2. 添加元素 
  ///multimap不支持下标操作 
  mapStudent.insert(pair<int, string>(0, "student_one")); 
  mapStudent.insert(pair<int, string>(0, "student_one_copy"));///一对多 
  mapStudent.insert(pair<int, string>(1, "student_two")); 
  mapStudent.insert(pair<int, string>(5, "Fear Kubrick")); 
  mapStudent.insert(pair<int, string>(2, "Akemi Homura")); 
  mapStudent.insert(pair<int, string>(-1, "Eren Jaeger")); 
  mapStudent.insert(pair<int, string>(99, "lin")); 
  cout << mapStudent.size() << endl; 
  cout << endl; 
   
  ///3. 遍历 
  for (iter = mapStudent.begin(); iter != mapStudent.end(); iter++) 
    cout << iter->first << " " << iter->second << endl; 
  cout << endl; 
   
  ///4. 单键查询与范围查询 
  ///单键查询 
  int count = mapStudent.count(0); 
  iter = mapStudent.find(0); 
  for (int i = 0; i < count; i++, iter++) 
    cout << iter->first << " " << iter->second << endl; 
  cout << endl; 
  ///范围查询 
  beg = mapStudent.lower_bound(1);/// >=1 
  end = mapStudent.upper_bound(5);/// <=5 
  for (; beg != end; beg++) 
    cout << beg->first << " " << beg->second << endl; 
  cout << endl; 
   
  ///5. 删除 
  iter = mapStudent.find(1); 
  mapStudent.erase(iter); 
  cout << mapStudent.size() << endl; 
  for (iter = mapStudent.begin(); iter != mapStudent.end(); iter++) 
    cout << iter->first << " " << iter->second << endl; 
  cout << endl; 
   
  ///6. 判空与清空 
  if (!mapStudent.empty()) 
    mapStudent.clear(); 
} 

/*请务必运行以下程序后对照阅读*/ 
 
///头文件依旧为set 
#include <set> 
#include <iostream> 
using namespace std; 
 
int main() 
{ 
  ///1. 初始化 
  multiset<int> num; 
  multiset<int>::iterator iter,beg,end; 
  cout << num.max_size() << endl;///multiset容纳上限 
  cout << endl; 
 
  ///2. 添加元素 
  for (int i = 0; i < 10; i++) 
    num.insert(i); 
  cout << num.size() << endl; 
  cout << endl; 
 
  ///3. 遍历 
  for (iter = num.begin(); iter != num.end(); iter++) 
    cout << *iter << " " ; 
  cout << endl; 
  cout << endl; 
 
  ///4. 查询 
 
  iter = num.find(1); 
  if (iter != num.end()) 
    cout << *iter << endl; 
  else 
    cout << -1 << endl; 
 
  iter = num.find(99); 
  if (iter != num.end()) 
    cout << *iter << endl; 
  else 
    cout << -1 << endl; 
  cout << endl; 
 
  beg=num.lower_bound(2); 
  end=num.upper_bound(7); 
  for (; beg != end; beg++) 
    cout << *beg << " " ; 
  cout << endl; 
 
  ///5. 删除 
  iter = num.find(1); 
  num.erase(iter); 
  cout << num.size() << endl; 
  for (iter = num.begin(); iter != num.end(); iter++) 
    cout << *iter << " " ; 
  cout << endl; 
  cout << endl; 
 
  ///6. 判空与清空 
  if (!num.empty()) 
    num.clear(); 
}