zoj 2727 List the Book

//虽然是一道水题，但是需要考虑的方面也挺多的，最开始没有考虑到需要进行三级排序：名字>年份>价格
//考虑到三级排序之后又没有考虑到格式，哎，编程真的很需要细腻的心思！所以WA了几次！下次需要注意了！
#include "iostream"
#include "vector"
#include "string"
#include "algorithm"
using namespace std;

struct Info//存储书的信息
{
string name;
int year;
int price;
};

//重载sort的比较符号，每一个的比较函数中都需要考虑三级排序！
bool mycomp1(Info a, Info b)
{
if (a.name == b.name)
{
if (a.year == b.year)
return a.price < b.price;
else
return a.year < b.year ;
}
else
return a.name < b.name;
}

bool mycomp2(Info a, Info b)
{
if (a.price == b.price)
{
if (a.name == b.name)
return a.year < b.year;
else
return a.name < b.name;
}
else
return a.price < b.price;
}

bool mycomp3(Info a, Info b)
{
if (a.year == b.year)
{
if (a.name == b.name)
return a.price < b.price;
else
return a.name < b.name;
}
else
return a.year < b.year;
}

int main()
{
int Num;
int F = 0;
while (cin >> Num && Num != 0)
{
if (F) cout << endl;//格式输出的控制！
Info *a = new Info[Num];
string flag;
vector<Info> v;
vector<Info>::iterator it;
for (int i = 0; i < Num; i++)
{
cin >> a[i].name >> a[i].year >> a[i].price;
v.push_back(a[i]);
}

cin >> flag;
if (flag == "Year")
sort(v.begin(), v.end(), mycomp3);
else if (flag == "Price")
sort(v.begin(), v.end(), mycomp2);
else if (flag == "Name")
sort(v.begin(), v.end(), mycomp1);

for (it = v.begin(); it != v.end(); it++)
cout << it->name << " " << it->year << " " << it->price << endl;
F++;
}
}