如何在C ++中为高分辨率时钟声明变量? [英] How to declare a variable for high resolution clock in C++?

问题描述

在此处的示例中: https://en.cppreference.com/w/cpp/chrono/high_resolution_clock/now

他们用auto声明了时钟时间点.

They declared the clock time point with auto.

auto start = std::chrono::high_resolution_clock::now();

医生说它返回代表当前时间的时间点".

and the doc says it returns 'A time point representing the current time.'

但是我不确定如何在下面的代码中进行声明，因为我习惯于在函数的开头声明变量，并且不知道将其声明为什么.这里的代码已简化以显示我的意思.我要为???做什么?

But I am not sure how do declare in my code below because I am used to declaring the variables at the beginning of the function and I don't know what to declare it as. Code has been simplified here to show what I mean. What do I put for the ????

我已经在那里尝试了auto，但是编译器不允许这样做. auto orderRecvedTime;给我这个错误:

I already tried auto there but the compiler won't allow it. auto orderRecvedTime; gives me this error:

error: non-static data member declared with placeholder 'auto'

#include <iostream>
#include <iterator>
#include <sstream>
#include <string>
#include <string.h>
//#include "load_symbol.h"
//#include "check_symbol.h"
#include "windows.h"
#include <vector>
#include <chrono>
using namespace std;

 

class order {
  private:
    string orderID;
    ???    orderRecvedTime;
    char   buysell;
    string symbol;
    double price;
    int    qty;

  public:
    void newOrder(string &_orderID, char &_buysell, string &_symbol, double &_price, int &_qty){
        orderID = _orderID;
        buysell = _buysell;
        symbol = _symbol;
        price = _price;
        qty = _qty;
        orderRecvedTime = std::chrono::high_resolution_clock::now();
    }
  
};



int main() {
    cout << "!!!Hello once more" << endl; // prints !!!Hello once more

    vector<order> thebook;
    string user_order = "";

    string done = "done trading";
    string orderID;
    string orderaction;
    string orderRecvedTime;
    char buysell;
    string symbol;
    double price;
    int qty;

    while (user_order.compare(done) != 0) {
        cout << "enter order"<< endl;
        getline(cin, user_order);

        stringstream lineStream(user_order);
        lineStream >>orderaction>>orderID>> buysell >> symbol >> price>> qty;
 
        order user_order;
        if (orderaction.compare("D") == 0) {
            cout << "you are making a new order."<< endl;
            user_order.newOrder(orderID, buysell,symbol,price,qty);
            thebook.push_back(user_order);
        }
    }
}

推荐答案

std::chrono::high_resolution_clock::time_point orderRecvedTime;

在实践中，high_resolution_clock是system_clock或steady_clock的类型别名，所以我的建议是选择其中之一，以提供可移植的体验.

In practice, high_resolution_clock is a type alias for either system_clock or steady_clock, so my advice is to choose either one of those instead for a portable experience.

• system_clock就像手表.它可以告诉您现在几点了.
• steady_clock就像秒表.对时间安排计时确实很不错，但实际上却不知道一天中的时间.

• system_clock is like a watch. It can tell you what time it is.
• steady_clock is like a stop watch. It is really good for timing things, but doesn't really know the time of day.

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