Measure execution time of a function in C++

#include <chrono>
using namespace std::chrono;

// Use auto keyword to avoid typing long
// type definitions to get the timepoint
// at this instant use function now()
auto start = high_resolution_clock::now();

#include <chrono>
using namespace std::chrono;

// After function call
auto stop = high_resolution_clock::now();

// Subtract stop and start timepoints and
// cast it to required unit. Predefined units
// are nanoseconds, microseconds, milliseconds,
// seconds, minutes, hours. Use duration_cast()
// function.
auto duration = duration_cast<microseconds>(stop - start);

// To get the value of duration use the count()
// member function on the duration object
cout << duration.count() << endl;

// C++ program to find out execution time of
// of functions
#include <algorithm>
#include <chrono>
#include <iostream>
#include<vector>
using namespace std;
using namespace std::chrono;

// For demonstration purpose, we will fill up
// a vector with random integers and then sort
// them using sort function. We fill record
// and print the time required by sort function
int main()
{

    vector<int> values(10000);

    // Generate Random values
    auto f = []() -> int { return rand() % 10000; };

    // Fill up the vector
    generate(values.begin(), values.end(), f);

    // Get starting timepoint
    auto start = high_resolution_clock::now();

    // Call the function, here sort()
    sort(values.begin(), values.end());

    // Get ending timepoint
    auto stop = high_resolution_clock::now();

    // Get duration. Substart timepoints to 
    // get duration. To cast it to proper unit
    // use duration cast method
    auto duration = duration_cast<microseconds>(stop - start);

    cout << "Time taken by function: "
         << duration.count() << " microseconds" << endl;

    return 0;
}