[C, C++](EN) Measure code running time by using clock() function
Measure code running time by using clock() function in c or cpp.
Environment and Prerequisite
- C, C++
Usage and Example
Usage
clock(): It is a function in time.h which returns the processor time consumed by the program. We can consider it as processor running time consumed by programclock_t: Return type of clock() function. It involves data type of clock ticks.CLOCKS_PER_SEC: It is a macro which represents clock ticks per second. Its value depends on system. Use this for human-readable time.
#include <stdio.h>
#include <time.h> // include time.h
int main(){
clock_t start = clock(); // save start time
// Code Here!!!
clock_t end = clock(); // save end time
// Print measured time
// Unit: second
// Dividing a count of clock ticks by this expression yields the number of seconds.
printf("Time: %lf\n", (double)(end - start)/CLOCKS_PER_SEC);
return 0;
}
Example
- Measuring nested loop iteration time.
#include <stdio.h>
#include <time.h> // include time.h
#define ITERATION_TIME 100000
int main (){
clock_t start = clock(); // save start time
for(int i = 0; i < ITERATION_TIME; ++i){
for(int j = 0; j < ITERATION_TIME; ++j)
int do_something;
}
clock_t end = clock(); // save end time
// Print measured time
// Unit: second
// Dividing a count of clock ticks by this expression yields the number of seconds.
printf("Time: %lf\n",(double)(end - start)/CLOCKS_PER_SEC);
}
- Result
$ g++ practice_board.cpp -o practice_board
$ ./practice_board
Time: 18.825036