Easily measure elapsed time

Question

I am trying to use time() to measure various points of my program.

What I don\'t understand is why the values in the before and after are the same? I understand thi

Answer 1

In answer to OP's three specific questions.

"What I don't understand is why the values in the before and after are the same?"

The first question and sample code shows that time() has a resolution of 1 second, so the answer has to be that the two functions execute in less than 1 second. But occasionally it will (apparently illogically) inform 1 second if the two timer marks straddle a one second boundary.

The next example uses gettimeofday() which fills this struct

struct timeval {
    time_t      tv_sec;     /* seconds */
    suseconds_t tv_usec;    /* microseconds */
};

and the second question asks: "How do I read a result of **time taken = 0 26339? Does that mean 26,339 nanoseconds = 26.3 msec?"

My second answer is the time taken is 0 seconds and 26339 microseconds, that is 0.026339 seconds, which bears out the first example executing in less than 1 second.

The third question asks: "What about **time taken = 4 45025, does that mean 4 seconds and 25 msec?"

My third answer is the time taken is 4 seconds and 45025 microseconds, that is 4.045025 seconds, which shows that OP has altered the tasks performed by the two functions which he previously timed.