看懂STL中的sort排序
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2024-01-26 12:49:16
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该例子旨在说明对于自定义类型如何做排序:
方法1:重载"<"或者">"运算符,对于less函数,对应重载<,对于greater函数,对应重载>;
方法2:采用自己写的比较函数,将函数名当做形参传入sort函数中去,如:sort(v.begin(),v.end(),MysortFunction);
方法1:重载"<"或者">"运算符,对于less函数,对应重载<,对于greater函数,对应重载>;
方法2:采用自己写的比较函数,将函数名当做形参传入sort函数中去,如:sort(v.begin(),v.end(),MysortFunction);
代码测试:
#include <iostream>
#include <algorithm>
#include <functional>
#include <vector>
#include <string>
using namespace std;
class student{
public:
student(const string &a, int b) :name(a), score(b){}
string name;
int score;
bool operator < (const student &m)const //重载小于号
{
return score < m.score;
}
bool operator > (const student &m)const //重载大于号
{
return score > m.score;
}
};
//自定义比较函数
bool MySortFunction(const student &a, const student &b)
{
return a.score < b.score;
}
int main() {
vector< student> vect;
student st1("Tom", 74);
vect.push_back(st1);
st1.name = "Jimy";
st1.score = 56;
vect.push_back(st1);
st1.name = "Mary";
st1.score = 92;
vect.push_back(st1);
st1.name = "Jessy";
st1.score = 85;
vect.push_back(st1);
st1.name = "Jone";
st1.score = 56;
vect.push_back(st1);
st1.name = "Bush";
st1.score = 52;
vect.push_back(st1);
st1.name = "Winter";
st1.score = 77;
vect.push_back(st1);
st1.name = "Andyer";
st1.score = 63;
vect.push_back(st1);
st1.name = "Lily";
st1.score = 76;
vect.push_back(st1);
st1.name = "Maryia";
st1.score = 89;
vect.push_back(st1);
cout << "---------------原有数据------------------" << endl;
for (int i = 0; i < vect.size(); i++)
cout << vect[i].name << ":\t" << vect[i].score << endl;
cout << "---------------重载小于号升序排序------------" << endl;
stable_sort(vect.begin(), vect.end(), less<student>());
for (int i = 0; i < vect.size(); i++)
cout << vect[i].name << ":\t" << vect[i].score << endl;
cout << "---------------重载大于号降序排序------------" << endl;
stable_sort(vect.begin(), vect.end(), greater<student>());
for (int i = 0; i < vect.size(); i++)
cout << vect[i].name << ":\t" << vect[i].score << endl;
cout << "---------------自己写升序比较函数------------" << endl;
stable_sort(vect.begin(), vect.end(), MySortFunction);
for (int i = 0; i < vect.size(); i++)
cout << vect[i].name << ":\t" << vect[i].score << endl;
return 0;
}
运行结果:
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