C++ 为什么赢了'；我的执行时间不能写在文件中吗？

我正在使用Chrono库来计算我的特定代码行的执行时间。我能够计算执行时间，但当我试图将其写入文件时，会出现各种错误。 我得到的错误是：

---

操作员不匹配持续时间的问题可以通过

duration\u cast

解决，另一个问题是行

int*arr=new int（sizeof（int）*n）int

，其值为

sizeof（int）*n

。您可能还想使用更好的随机数生成器。代码中的建议：

#include <iostream>
#include <fstream>
#include <chrono>
#include <vector> // std::vector
#include <random> // std::random

int main ()
{
    std::random_device rd;
    std::mt19937 generator(rd()); // seed a prng
    // and create a distribution object:
    std::uniform_int_distribution<int> rnd_dist(1, 1000); // [1,1000]

    // you can open the file directly like this:
    std::ofstream plot("graph.txt");
    // and check if it was opened successfully:
    if(!plot) {
        std::clog << "couldn't open file\n";
        return 1;
    }

    // I'll use a std::random generator instead of this:
    // srand((unsigned)time(0));

    int n = 250;
    std::cout <<"The size of the array is:" << n << "\n\n";

    plot << n; // you probably want  << "\n";  here
    // You had:
    //   int *arr = new int (sizeof(int)*n);
    // It should have been:
    //   int *arr = new int[n];
    // but the below is better since you don't have to delete[] it manually:
    std::vector<int> arr(n);

    for (int i=0; i<n; ++i) {
        arr[i] = rnd_dist(generator);
    }

    std::cout << "The array provided is:\n";
    for (int i=0; i<n; ++i) {
        std::cout << arr[i] << " ";
    }
    std::cout << "\n\n";

    // Edit: changed to high_resolution_clock
    auto start = std::chrono::high_resolution_clock::now();
    // the below call works, but consider changing the signaure of your Selectionsort() to:
    // void Selectionsort(std::vector<int>& arr);
    // The "n" is available via "arr.size();"
    Selectionsort(arr.data(), arr.size());
    auto end = std::chrono::high_resolution_clock::now();
    // diffe duration_cast fix:
    auto diffe = std::chrono::duration_cast<std::chrono::milliseconds>(end-start);
    plot << diffe.count(); // you probably want  << "\n";  here
    std::cout << "The execution time for average case is: " << diffe.count() << " ms\n";
}

#包括
#包括
#包括
#include//std:：vector
#include//std:：random
int main（）
{
std：：随机_装置rd；
std:：mt19937生成器（rd（））；//为prng种子
//并创建分发对象：
标准：统一国际分布区域（11000）；/[11000]
//您可以像这样直接打开文件：
std：：流图（“graph.txt”）；
//并检查是否已成功打开：
如果（！绘图）{
std:：clog从输出语句中删除类型声明：
std:：难道您没有
diff
的声明吗？您是想使用
diff
？
newint（sizeof（int）*n）
分配一个
int
值
sizeof（int）*n
。建议清理此问题并生成一个。如果制作MCVE不会向您暴露您的问题，请编辑此问题以包含MCVE。是的，我打算使用Differ。很抱歉输入错误，但即使我使用Differ，我仍然收到错误您好，谢谢您的代码。我终于可以执行我的代码并将执行时间写入一个文件中，但问题是它显示的执行时间是0毫秒。@AyushPoudel可能是您的
Selectionsort
太快，稳定的时钟无法注意到。我在答案中更改为
high\u resolution\u clock
。也许这会注意到一个差异。您还可以尝试将
duration\u cast
转换为
std:：chrono:：microseconds
以查看这是否会产生影响。我将其更改为高分辨率时钟，并大幅增加了阵列的大小，但它仍然给我0毫秒。如果我这样做：auto Differ=end start；我确实以毫秒为单位获取时间，但当我尝试使用plot将其写入文件时，您是否检查过阵列是否真的进行了排序？是的，th数组被排序了，我在之前的评论中做了一些编辑。你能检查一下吗
#include <iostream>
#include <fstream>
#include <chrono>
#include <vector> // std::vector
#include <random> // std::random

int main ()
{
    std::random_device rd;
    std::mt19937 generator(rd()); // seed a prng
    // and create a distribution object:
    std::uniform_int_distribution<int> rnd_dist(1, 1000); // [1,1000]

    // you can open the file directly like this:
    std::ofstream plot("graph.txt");
    // and check if it was opened successfully:
    if(!plot) {
        std::clog << "couldn't open file\n";
        return 1;
    }

    // I'll use a std::random generator instead of this:
    // srand((unsigned)time(0));

    int n = 250;
    std::cout <<"The size of the array is:" << n << "\n\n";

    plot << n; // you probably want  << "\n";  here
    // You had:
    //   int *arr = new int (sizeof(int)*n);
    // It should have been:
    //   int *arr = new int[n];
    // but the below is better since you don't have to delete[] it manually:
    std::vector<int> arr(n);

    for (int i=0; i<n; ++i) {
        arr[i] = rnd_dist(generator);
    }

    std::cout << "The array provided is:\n";
    for (int i=0; i<n; ++i) {
        std::cout << arr[i] << " ";
    }
    std::cout << "\n\n";

    // Edit: changed to high_resolution_clock
    auto start = std::chrono::high_resolution_clock::now();
    // the below call works, but consider changing the signaure of your Selectionsort() to:
    // void Selectionsort(std::vector<int>& arr);
    // The "n" is available via "arr.size();"
    Selectionsort(arr.data(), arr.size());
    auto end = std::chrono::high_resolution_clock::now();
    // diffe duration_cast fix:
    auto diffe = std::chrono::duration_cast<std::chrono::milliseconds>(end-start);
    plot << diffe.count(); // you probably want  << "\n";  here
    std::cout << "The execution time for average case is: " << diffe.count() << " ms\n";
}