用sort实现对struct的排序

用sort 排序 struct

+++

//method 1
struct node{
    int k,s;
}p[5005];
bool cmp1(node x,node y){
    return x.s>y.s;   //定义降序排序（从大到小）
}
bool cmp2(node x,node y){
    return x.k<y.k;   //定义升序排序（从小到大）
}sort(p+1,p+n+1,cmp2); //排序

eg:

#include<iostream>
#include<algorithm>
using namespace std;
struct b {
	int k, s;
};
bool compare(b x, b y)
{
	if (x.k != y.k)	return x.k > y.k;
	return x.s > y.s;//降序排序
}
int main()
{
	b p[5] = { {2, 4}, {2, 8}, {5, 9}, {1, 4}, {2, 5} };
	sort(p, p + 5, compare);//point
	for (auto x : p)
		cout << x.k << " " << x.s << endl;
	system("pause");
	return 0;
}

//method 2
struct b {
	int k, s;
	bool operator< (const b & t)const//实现降序排序
	{
		if (k != t.k)	return k < t.k;
		return s < t.s;
	}
};

eg:

#include<iostream>
#include<algorithm>
using namespace std;
struct b {
	int k, s;
	bool operator< (const b & t)const
	{
		if (k != t.k)	return k < t.k;
		return s < t.s;
	}
};
int main()
{
	b p[5] = { {2, 4}, {2, 8}, {5, 9}, {1, 4}, {2, 5} };
	sort(p, p + 5);//参数只需要两个迭代器，不需要第三个参数
	for (auto x : p)
		cout << x.k << " " << x.s << endl;
	system("pause");
	return 0;
}