C++关联容器 Multiset and set

/******************set*/
#include <iostream>
#include <set>
#include <algorithm>
#include <iterator>
using namespace std;
typedef set<double,less<double> > DoubleSet;//注意> >间距
int main()
{   
    const int SIZE=5;
    double a[SIZE] = {2.1,4.2,9.5,2.1,3.7};
    DoubleSet dd(a,a+SIZE);
    ostream_iterator<double> output(cout," ");
    cout<<"Double Set Contains: ";
    copy(dd.begin(),dd.end(),output);

    pair<DoubleSet::const_iterator,bool> p;  //定义一个pair对象，由DoubleSet的const_iterator和一个布尔值组成        
    p=dd.insert(13.8); //因为容器没有13.8,13.8被插入，则p.first指向13.8,p.second返回为真
    cout<<"\n\n"<<*(p.first)<<(p.second?" was ":" was not ")<<" insertd";

    cout<<"\nDoubleset contains:";
    copy(dd.begin(),dd.end(),output);
    p=dd.insert(9.5);//因为set关联容器不允许重复,9.5已经存在,故没有被插入,p.second返回为假
    cout<<"\n\n"<<*(p.first)<<(p.second?" was ":" was not ")<<" insertd";
    
    cout<<"\nDoubleset contains:";
    copy(dd.begin(),dd.end(),output);
    cout<<endl;

}

muntiset

#include <iostream>
#include <set>
#include <algorithm>
#include <iterator>
using namespace std;
typedef multiset<int,less<int> > Ims;//注意> >间距
int main()
{   
    const int SIZE = 10;
    int a[SIZE]={7,22,9,1,18,30,100,22,85,13};
    Ims intMultiset;
    ostream_iterator<int> output(cout," ");
    cout<<"There are Curently"<<intMultiset.count(15)<<"values of 15 in the multiset\n\n";
    intMultiset.insert(15);
    intMultiset.insert(15);
    cout<<"\nAfter insert,there are "<<intMultiset.count(15)<<" values of 15 in the multiset\n\n";

    Ims::const_iterator result;
    result=intMultiset.find(15);

    if(result!=intMultiset.end())
        cout<<"Fond values 15\n";
  result=intMultiset.find(20);
  if(result==intMultiset.end())
  cout<<"Did not Find values 20\n";
 intMultiset.insert(a,a+SIZE);
 cout<<"\nAfter insert,int multiset contains:\n";
 copy(intMultiset.begin(),intMultiset.end(),output);
 cout<<"\n\nLower bound of 22: "<<*(intMultiset.lower_bound(22));
 cout<<"\n\nUpper bound of 22: "<<*(intMultiset.upper_bound(22));

 pair<Ims::const_iterator,Ims::const_iterator> p;//p包含两个成员first,second
 p=intMultiset.equal_range(22);//这里使用equal_range函数确定值22在intmultiset中最早出现的位置和最后一次出现的位置
 cout<<"\n\nequal_range of 22 :"<<"\n Lower bound: "
     <<*(p.first)<<"\n Upper bound"<<*(p.second);
 cout<<endl;
    return 0;
}

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