sort函数默认是按升序排序的，当然你也可以按照降序排序。
不过需要你自己写比较函数，下面给你一个例子，你自己参看写。
#include
#include
#include
#include
using namespace std;
class myclass {
public:
myclass(int a, int b):first(a), second(b){}
int first;
int second;
bool operator < (const myclass &m)const {
return first < m.first;
}
};
bool less_second(const myclass & m1, const myclass & m2) {
return m1.second < m2.second;
}
int main() {
vector< myclass > vect;
for(int i = 0 ; i < 10 ; i ++){
myclass my(10-i, i*3);
vect.push_back(my);
}
for(int i = 0 ; i < vect.size(); i ++)
cout<<"("< sort(vect.begin(), vect.end());
cout<<"after sorted by first:"< for(int i = 0 ; i < vect.size(); i ++)
cout<<"("< cout<<"after sorted by second:"< sort(vect.begin(), vect.end(), less_second);
for(int i = 0 ; i < vect.size(); i ++)
cout<<"("<
return 0 ;
}
输出结果：
(10,0)
(9,3)
(8,6)
(7,9)
(6,12)
(5,15)
(4,18)
(3,21)
(2,24)
(1,27)
after sorted by first:
(1,27)
(2,24)
(3,21)
(4,18)
(5,15)
(6,12)
(7,9)
(8,6)
(9,3)
(10,0)
after sorted by second:
(10,0)
(9,3)
(8,6)
(7,9)
(6,12)
(5,15)
(4,18)
(3,21)
(2,24)
(1,27)
