c++ - 没有用于调用 std::vector<std::tuple> push_back 的匹配函数

Question

我有一个包含 6 个时间点的示例程序，使用 high_resolution_clock::now()来自标准chrono header 。我将它们中的每一个差异化为 3 个差异并将它们归类为 auto duration1 = std::chrono::duration_cast<std::chrono::microseconds>( t2 - t1 ).count();到微秒。

我有另一个名为 durations 的变量，其分配如下:auto durations = std::make_tuple(duration1,duration2,duration3);包含之前的时间点差异。

我必须将这个元组插入一个 vector ，所以我引入了 std::vector<std::tuple<std::chrono::microseconds,std::chrono::microseconds,std::chrono::microseconds>> list;但是在使用 list.push_back(durations);我得到一个错误:

prog.cpp: In function 'int main()':
prog.cpp:36:29: error: no matching function for call to 'std::vector<std::tuple<std::chrono::duration<long long int, std::ratio<1ll, 1000000ll> >, std::chrono::duration<long long int, std::ratio<1ll, 1000000ll> >, std::chrono::duration<long long int, std::ratio<1ll, 1000000ll> > > >::push_back(std::tuple<long long int, long long int, long long int>&)'
     list.push_back(durations);

---

我试图搜索关于 std::chrono::microseconds 的内容及其他std::chrono::duration东西here但未能成功解决问题。

我知道这与我对类型系统的疏忽有关，但我无法找到该错误。任何帮助将不胜感激，这里是 ideone link .

#include <iostream>
#include <chrono>
#include <vector>
#include <tuple>

using namespace std;
using namespace std::chrono;

void function()
{
    long long number = 0;

    for( long long i = 0; i != 2000000; ++i )
    {
       number += 5;
    }
}

int main()
{
    high_resolution_clock::time_point t1 = high_resolution_clock::now();
    high_resolution_clock::time_point t3 = high_resolution_clock::now();
    high_resolution_clock::time_point t5 = high_resolution_clock::now();
    function();
    high_resolution_clock::time_point t2 = high_resolution_clock::now();
    high_resolution_clock::time_point t4 = high_resolution_clock::now();
    high_resolution_clock::time_point t6 = high_resolution_clock::now();

    auto duration1 = std::chrono::duration_cast<std::chrono::microseconds>( t2 - t1 ).count();
    auto duration2 = std::chrono::duration_cast<std::chrono::microseconds>( t4 - t3 ).count();
    auto duration3 = std::chrono::duration_cast<std::chrono::microseconds>( t6 - t5 ).count();

    auto durations = std::make_tuple(duration1,duration2,duration3);

    std::vector<std::tuple<std::chrono::microseconds,std::chrono::microseconds,std::chrono::microseconds>> list;
    list.push_back(durations);

    cout << duration1 << " -- "<< duration2 << " -- "<< duration3 << " -- ";
    return 0;
}

Answer 1

您已经创建了一个包含 3 个整数的元组，并且您正在尝试将它添加到一个包含 3 个持续时间的 vector 。

I take differences b/w each of them resulting in 3 differences and caste them as auto duration1 = std::chrono::duration_cast<std::chrono::microseconds>( t2 - t1 ).count(); to microseconds.

你为什么调用 count()关于执行 duration_cast 后的持续时间转换为微秒？

只需将值保持为 microseconds对象，您可以将它们添加到 vector 中:

auto duration1 = std::chrono::duration_cast<std::chrono::microseconds>( t2 - t1 );
auto duration2 = std::chrono::duration_cast<std::chrono::microseconds>( t4 - t3 );
auto duration3 = std::chrono::duration_cast<std::chrono::microseconds>( t6 - t5 );