Question

How to measure execution time of a function in C++

Answer 1

#include <iostream>
#include <chrono>
#include <thread>
 
void sleep(int sec) {
    std::this_thread::sleep_for(std::chrono::seconds(sec));
}
 
int main() {
 
    auto start = std::chrono::high_resolution_clock::now();
     
    sleep(4);
     
    auto end = std::chrono::high_resolution_clock::now();
 
    auto time_in_seconds = std::chrono::duration_cast<std::chrono::seconds>(end - start);
 
    std::cout << time_in_seconds.count() << " seconds";
}
  
  
  
  
/*
run:
  
4 seconds
  
*/

 

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Answer 2

#include <iostream>
#include <chrono>
#include <thread>
  
void sleep(int sec) {
    std::this_thread::sleep_for(std::chrono::seconds(sec));
}
  
int main() {
  
    auto start = std::chrono::high_resolution_clock::now();
      
    sleep(4);
      
    auto end = std::chrono::high_resolution_clock::now();
  
    std::chrono::duration<double, std::milli> timi_in_milliseconds = end - start;
  
    std::cout << timi_in_milliseconds.count() << " ms";
}
   
   
   
   
/*
run:
   
4000.15 ms
   
*/

 

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Answer 3

#include <iostream>
#include <chrono>
#include <thread>
  
void sleep(int sec) {
    std::this_thread::sleep_for(std::chrono::seconds(sec));
}

int main() {
    auto start = std::chrono::high_resolution_clock::now();
    
    sleep(4);
   
    auto finish = std::chrono::high_resolution_clock::now();
    
    auto time_in_nanoseconds = std::chrono::duration_cast<std::chrono::nanoseconds>(finish - start).count();
    
    std::cout << time_in_nanoseconds << " ns";
}

   
   
   
/*
run:
   
4000103259 ns
   
*/

 

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Answer 4

#include <iostream>
#include <chrono>
#include <thread>
   
void sleep(int sec) {
    std::this_thread::sleep_for(std::chrono::seconds(sec));
}
 
int main() {
    auto start = std::chrono::high_resolution_clock::now();
     
    sleep(4);
    
    auto finish = std::chrono::high_resolution_clock::now();
     
    auto time_in_microseconds = std::chrono::duration_cast<std::chrono::microseconds>(finish - start).count();
     
    std::cout << time_in_microseconds << " µs";
}
 
    
    
    
/*
run:
    
4000056 µs
    
*/

 

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