...vector的sort算法对元素是自定义类型进行排序

发布网友发布时间：2024-04-07 17:25

共3个回答

热心网友时间：2024-07-22 05:35

自己写一个比较函数就可以了，作为第三个参数传到sort函数。

下面有个小例子：

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

class AbA
{
public:
int m_nA;
int m_nB;
AbA(int a, int b) : m_nA(a), m_nB(b){}
};

ostream& operator << (ostream& os, const AbA& ra)
{
os << ra.m_nA << " " << ra.m_nB;
return os;
}

// 自己写的比较函数
bool newLess(const AbA& ra, const AbA& rb)
{
return (ra.m_nA < rb.m_nA );
}
int main()
{
vector<AbA> vecAbA;
vecAbA.push_back(AbA(1, 2));
vecAbA.push_back(AbA(7, 8));
vecAbA.push_back(AbA(5, 6));
vecAbA.push_back(AbA(3, 4));

sort(vecAbA.begin(), vecAbA.end(), newLess);
for (int i = 0; i < vecAbA.size(); i++)
{
cout << vecAbA[i] << " ";
}
return 0;
}

朋友，请【采纳答案】，您的采纳是我答题的动力，如果没有明白，请追问。谢谢。

热心网友时间：2024-07-22 05:39

#include <vector>
#include <iostream>
#include <string>
#include <algorithm> //sort函数头文件

using namespace std;

class Student {
public:
int m_num;
string m_name;

public:

Student(int n,string name)
:m_num(n),m_name(name)
{

}

void display() const{
cout << "姓名：" << m_name << " ,学号：" << m_num << endl;
}
};
//自定义的比较函数,这里是对学号进行排序
static bool myCompare(const Student& a1,const Student& a2)
{
return a1.m_num <= a2.m_num;
}

int main()
{
//创建4个学生
vector<Student> classOne;
Student a1(2,"a");
classOne.push_back(a1);
Student a2(4,"b");
classOne.push_back(a2);
Student a3(5,"c");
classOne.push_back(a3);
Student a4(1,"d");
classOne.push_back(a4);

cout << "排序前：" << endl;
vector<Student>::iterator it = classOne.begin();
while (it != classOne.end())
{
it->display();
++it;
}

sort(classOne.begin(), classOne.end(),myCompare);
cout << "排序后：" << endl;
it = classOne.begin();
while (it != classOne.end())
{
it->display();
++it;
}
return 0;
}

热心网友时间：2024-07-22 05:34

你好，可以利用map实现。以下是代码，请参考：//copyright@quark//date:2010-10-19#include#include#include#includeusingnamespacestd;voidpaixu(vector&ivec,inttopnum)//选出出现次数最多的topnum个，其余删除{vector::iteratoriter=ivec.begin();mapm;for(iter;iter!=ivec.end();++iter){m[*iter]++;}if(topnum>m.count()){return;}//循环遍历map对象，输出最多出现的元素for(inti=0;imaxPair;map::const_iteratoriter=m.begin();while(iter!=m.end()){if((*iter).second>maxPair.second){maxPair=*iter;}iter++;}if(maxPair.second>0){coutivec;ivec.push_back(3);ivec.push_back(2);ivec.push_back(1);ivec.push_back(2);ivec.push_back(1);ivec.push_back(1);ivec.push_back(1);paixu(ivec,2);getchar();}