【STL】sort函数的用法

one：

 

#include <vector>
#include <algorithm> 
#include <iostream>
using namespace std;
bool compare(int s1, int s2)
{
	return s1>s2;
}
int main(int argc, char* argv[])
{
	vector<int> vec;
	vec.push_back (23);	vec.push_back (33);
	vec.push_back (2);		vec.push_back(44);
	vec.push_back(5);	
	sort(vec.begin(), vec.end(),compare);
	for (vector<int>::iterator i = vec.begin(); i != vec.end(); i++)
	{
		cout<<*i<<endl;
	}
	return 0;
}

输出：

44

33

23

5

2

 

two：

 

#include <vector>
#include <algorithm>
#include <iostream>
#include <string>
using namespace std;
class myless
{
public:
	bool operator()( const int &a, const int &b) 
	{
		return a < b;
    }
};
int main(int argc, char* argv[])
{
	 vector<int> vec;
	 vector<int>::iterator i;
	 vec.push_back (10);
	 vec.push_back (3);
	 vec.push_back (7);
	 sort(vec.begin(), vec.end(), myless());
	 for (i = vec.begin(); i != vec.end(); i++)
	 {
		cout<<*i<<endl;
	 }
	 return 0;
}

输出：

3

7

10

 

 

 

three：

 

#include <vector>
#include <algorithm>
#include <iostream>
#include <string>
using namespace std;
typedef struct
{
	 string first;
	 string last;
}NAME;
bool sortbyfirst(const NAME& n1, const NAME& n2)
{
	 return (n1.first<n2.first);
}
bool sortbylast(const NAME& n1, const NAME& n2)
{
	 return (n1.last<n2.last);
}
int main(int argc, char* argv[])
{
	 vector<NAME> contacts;
	 vector<NAME>::iterator j;
	 NAME tmp;
	 tmp.first = "liu";
	 tmp.last = "bei";
	 contacts.push_back(tmp);
	 tmp.first = "zhao";
	 tmp.last = "yun";
	 contacts.push_back(tmp);
	 tmp.first = "gun";
	 tmp.last = "yu";
	 contacts.push_back(tmp);
	 tmp.first = "zhang";
	 tmp.last = "fei";
	 contacts.push_back(tmp);
	cout<<"by first:"<<endl; 
	sort(contacts.begin(), contacts.end(), sortbyfirst);
	 for(j=contacts.begin(); j!= contacts.end(); j++)
	 {
		  cout<<j->first<<" "<<j->last<<endl;
	 }
	 cout<<"by last:"<<endl;
	 sort(contacts.begin(), contacts.end(), sortbylast);
	 for(j=contacts.begin(); j!= contacts.end(); j++)
	 {
		  cout<<j->first<<" "<<j->last<<endl;
	 }
	 return 0;
}

 

 

输出：

 

by first:
gun yu
liu bei
zhang fei
zhao yun
by last:
liu bei
zhang fei
gun yu
zhao yun
请按任意键继续. . .