c++学习stl的一个分组案例

//请问为啥没有输出结果

#include<iostream>
#include<vector>
#include<map>
#include<string>
#include<ctime>
#include<algorithm>
using namespace std;
class Print;
class Person
{
public:
    Person(int salary,string name);
    ~Person();

private:
    int m_Salary;
    string m_Name;

    friend void creatPerson(vector<Person>* v);
    friend void sortPerson(const vector<Person>& v, multimap<int, Person>* m); 
    friend class Print;
};

Person::Person(int salary,string name)
{
    m_Salary = salary;
    m_Name = name;
}

Person::~Person()
{
    
}

class Print
{
public:
    void operator()(const pair<int, Person>& p)
    {

        cout << "编号"<<p.first<<"\t工资" << p.second.m_Salary << "\t姓名" << p.second.m_Name << endl;
    }
};

void creatPerson(vector<Person>* v)
{
    char nameSeed[10] = { 'A','B','C','D','E','F','G','H','I','J'};
    for (int i = 0; i < 10; i++)
    {
        v->push_back(    Person (0, (const char*)nameSeed[i])        );
    }
}

void sortPerson(const vector<Person>& v, multimap<int, Person>* m)
{
    int id; 
    for (int i = 0; i < 10; i++)
    {
        id=rand() % 3 + 1;//1`3
        m->insert(make_pair(id, v[i]));        
    }
}




int main()
{
    vector<Person>v;
    creatPerson(&v);
    cout<<v.size()<<v.empty()  ;
    multimap<int, Person>m;
    sortPerson(v, &m);

    for_each(m.begin(),m.end(),Print());
    
}

51 行修改，要取 字符数组，不能取 字符转换，参考如下：

 
#include<iostream>
#include<vector>
#include<map>
#include<string>
#include<ctime>
#include<algorithm>
using namespace std;
class Print;
class Person
{
public:
    Person(int salary,string name);
    ~Person();
 
private:
    int m_Salary;
    string m_Name;
 
    friend void creatPerson(vector<Person>* v);
    friend void sortPerson(const vector<Person>& v, multimap<int, Person>* m); 
    friend class Print;
};
 
Person::Person(int salary,string name)
{
    m_Salary = salary;
    m_Name = name;
}
 
Person::~Person()
{
    
}
 
class Print
{
public:
    void operator()(const pair<int, Person>& p)
    {
 
        cout << "编号"<<p.first<<"\t工资" << p.second.m_Salary << "\t姓名" << p.second.m_Name << endl;
    }
};
 
void creatPerson(vector<Person>* v)
{
    char nameSeed[10] = { 'A','B','C','D','E','F','G','H','I','J'};
    for (int i = 0; i < 10; i++)
    {
        v->push_back(Person (0, (const char*)nameSeed)); // 修改
    }
}
 
void sortPerson(const vector<Person>& v, multimap<int, Person>* m)
{
    int id; 
    for (int i = 0; i < 10; i++)
    {
        id=rand() % 3 + 1;//1`3
        m->insert(make_pair(id, v[i]));        
    }
}
 
 
 
 
int main()
{
    vector<Person>v;
    creatPerson(&v);
    cout<<v.size()<<v.empty()  ;
    multimap<int, Person>m;
    sortPerson(v, &m);
 
    for_each(m.begin(),m.end(),Print());
    
}

• 这篇文章讲的很详细，请看：【C++学习五】STL库的应用
• 除此之外, 这篇博客: C++ STL容器使用中的 二分法 部分也许能够解决你的问题, 你可以仔细阅读以下内容或跳转源博客中阅读:
  

• #include<iostream>
  #include<vector>
  using namespace std;
  void output(vector<int> m_list)
  {
      for ( vector<int>::iterator it=m_list.begin(); it != m_list.end(); ++it) {
          cout<<*it<<endl;
      }
  }
  int  main()
  {
      vector<int> v(10);
      for (int var = 0; var < 10; ++var) {
         v[var] = var;
      }
      output(v);
      vector<int>::iterator it_begin=v.begin();
      vector<int>::iterator it_end=v.end();
      vector<int>::iterator it_mid=v.begin()+(it_end-it_begin)/2;
  
      int number;
      cin>>number;
  
      while(  it_begin < it_end){
  
          if(number < *it_mid){
              it_end = it_mid;
          }else if(number > *it_mid){
              it_begin = it_mid+1;
          }else{
              break;
          }
  
          it_mid = it_begin + (it_end - it_begin)/2;
      }
  
      if(number == *it_mid)
          cout<<"find"<<endl;
      else
          cout<<"oh no!"<<endl;
      return 0;
  }
  

• 您还可以看一下 夏曹俊老师的C++ STLSTL实战开发精讲视频课程中的 STL概论：六大组件的概要介绍小节, 巩固相关知识点