Code Warrior
Miscellaneous Tips
Time
C++ has a standard library named time.h.
It defines a class named time_t.
Defined constants:
NULL = 0;
Functions:
time(NULL); //always use NULL
usage:
time_t sec;
//create a time object named sec;
sec = time(NULL); //store the number of seconds
since 12:00 AM that began January 1, 1980.
difftime(t2,t1); //returns number of seconds (type int) elapsed from t1 to t2 (both of type time_t, t1 is the EARLIER time).
usage:
int elapse = difftime(t2,t1);
//store seconds elapsed from t1 to t2 in variable elapse.
putting it all together
Sample:
#include <time.h>
time_t Start_t, End_t;
int time_task1, time_task2;
Start_t = time(NULL); //record time that task 1 begins
//perform task 1 here
End_t = time(NULL); //record time that task 1 ends
time_task1 = difftime(End_t, Start_t); //compute
elapsed time of task 1
Start_t = time(NULL); //record time that task 2 begins
//perform task 2 here
End_t = time(NULL); //record time that task 2 ends
time_task2 = difftime(End_t, Start_t); //compute elapsed
time of task 2
cout << "Task 1 took " << setw(3) << time_task1 <<
" seconds.\n";
cout << "Task 2 took " << setw(3) << time_task2 <<
" seconds.\n";
clock();
This function returns a value of type long (also defined in the class as type clock_t), which is the number of milliseconds since 12:00 AM that began January 1, 1980, to the nearest 10 milliseconds. (So you get hundredths of a second reported in milliseconds).
This function may be used like the time() function, but is more useful
for measuring very short intervals of time.