C++ Vector

#include<stdio.h>
#include<algorithm>
#include<vector>
#include<iostream>
using namespace std;

typedef struct rect
{
    int id;
    int length;
    int width;
	//对于向量元素是结构体的，可在结构体内部定义比较函数，下面按照id,length,width升序排序。
	bool operator< (const rect &a)  const
	{
		if(id!=a.id)
			return id<a.id;
		else
		{
			if(length!=a.length)
				return length<a.length;
			else
				return width<a.width;
		}
    }
	rect operator- (const rect &a)  const
	{
		rect f;
		f.id = id - a.id;
		f.length = length-a.length;
		f.width = width-a.width;
		return f;
    }
}Rect;
int main()
{
    vector<Rect> vec;
    Rect rect,rect1;
    rect.id=1;
    rect.length=2;
    rect.width=3;
	rect1.id=2;
    rect1.length=2;
    rect1.width=3;
	if (rect<rect1)
	{
		printf("+++");
	}
    vec.push_back(rect);
	vec.push_back(rect1);	
    vector<Rect>::iterator it=vec.begin();
	for (;it<vec.end();it++)
	{
		cout<<(*it).id<<' '<<(*it).length<<' '<<(*it).width<<endl; 
	}	
	reverse(vec.begin(),vec.end());
	vector<Rect>::iterator itt=vec.begin();
	for (;itt<vec.end();itt++)
	{
		cout<<(*itt).id<<' '<<(*itt).length<<' '<<(*itt).width<<endl; 
	}
	sort(vec.begin(),vec.end());
	itt = vec.begin();
	for (;itt<vec.end();itt++)
	{
		cout<<(*itt).id<<' '<<(*itt).length<<' '<<(*itt).width<<endl; 
	}
	Rect ct = rect1 - rect;
	return 0;
}