C 11下计算时间差(毫秒)要用到chrono时间库,以下是示例代码，我从en.cppreference.com上抄来改的.
代码语言：javascript复制#include <iostream>
#include <iomanip>
#include <vector>
#include <numeric>
#include <chrono>
volatile int sink;
int main()
{
std::cout << std::fixed << std::setprecision(9) << std::left;
for (auto size = 1ull; size < 1000'000'000ull; size *= 100) {
// record start time
auto start = std::chrono::system_clock::now();
// do some work
std::vector<int> v(size, 42);
sink = std::accumulate(v.begin(), v.end(), 0u); // make sure it's a side effect
// record end time
auto end = std::chrono::system_clock::now();
std::chrono::duration<double> diff = end-start;
// 计算毫秒时间差并输出
// 如果要求其他时间单位可以修改 std::chrono::milliseconds 为其他类型
// 比如std::chrono::seconds
auto duration = std::chrono::duration_cast<std::chrono::milliseconds>(end - start);
std::cout << "Time to fill and iterate a vector of " << std::setw(9)
<< size << " ints : " << duration.count() << " msn";
}
}
