你们有没有会的啊，求解！！！！！！！

[XiaoErLeeIsGod]

如下
品种 日期 成交 持仓
A 9.2 10 21
B 9.2 12 21
C 9.2 33 32
S 9.3 22 21
F 9.3 11 11
怎样求出每天成交乘以持仓最大的那条记录，用C/C++写
输出为
品种 日期 成交 持仓
C 9.2 33 32
S 9.3 22 21

怎么写，怎么写

[Corner]

typedef struct 
{
#define DATE_LEN 10
    char type;          //品种
    char date[DATE_LEN];//日期，日期长度限制为9个字节
    int bargain_num;    //成交
    int position;       //持仓
}Commodities;

int GetMaxCommodity(Commodities* commodities, int num)
{
    //assert(commodities != NULL)
    int index = -1;
    int i;
    int max_num = -1;
    int tmp_num = 0;
    for(i = 0; i < num; i++)
    {
        tmp_num = (commodities + i)->bargain_num * (commodities + i)->position;
        if(max_num < tmp_num)
        {
            index = i;
            max_num = tmp_num;
        }
    }
    return index;
}

void test()
{
#define NUM 5
    Commodities commodities[NUM] = {
        {'A', "9.2", 10, 21},
        {'B', "9.2", 12, 21},
        {'C', "9.2", 33, 32},
        {'S', "9.3", 22, 21},
        {'F', "9.3", 11, 11},
    };
    int index = GetMaxCommodity(commodities, NUM);
    if(index != -1)
    {
        printf("%c %s %d %d", commodities[index].type, commodities[index].date, commodities[index].bargain_num, commodities[index].position);
    }
}

[mujiok2003]

#include <iostream>
#include <string>
#include <map>
#include <cassert>
#include <sstream>
class Record
{
public:
   Record() : value_(0.0)
   {}
    Record(std::string const& rec) : record_(rec)
    {
		std::istringstream iss(rec);
		//A 9.2 10 21
		std::string cat;
		double vol, stock;  
		std::getline(iss, cat, ' ');
		std::getline(iss, date_, ' ');
		iss >> vol >> stock;
		assert(iss);
		value_ = vol * stock;
	}	
	double value() const
	{
		return value_;
	}
	std::string toString() const
	{
		return record_;
	}
	std::string date() const
	{
		return date_;
	}
private:
 std::string record_;
 double value_;
 std::string date_;
};

int main()
{
	std::string line,title;
	std::getline(std::cin, title);
	std::map<std::string, Record> maxRecords; //date->record
	while(std::getline(std::cin, line))
	{
		Record r(line);
		std::string date = r.date();
		if(maxRecords[date].value() < r.value())
		{
			maxRecords[date] = r;
		}
	}
	std::cout << title << std::endl;
	for(std::map<std::string, Record>::iterator it = maxRecords.begin(); it != maxRecords.end(); ++it)
	{
		std::cout << it->second.toString() << std::endl;
	}
	return 0;
}

编译成main.exe后， 运行 main.exe < records.txt。 你记录保存在record.txt