Hello,
in the example below I'm interactively running 2 test routines which I
consider to be exactly the same from the point of view of execution:
the only difference between them consists in that one line which
*should never be executed* is uncommented in the second routine.
I'd also expect the execution times to be exactly the same.
However ROOT TStopwatch timer reports *very* strange results:
the reported times differ by more than a factor of 100...
One could either suspect TStopwatch timer in reporting wrong time in one
of 2 cases or CINT in doing much more than it has been asked to in case
when `cout ...' is uncommented.
I should also mention that replacing `cout' in test2 with `printf' makes
both times *exactly* the same in agreement with the expectations...
Could anybody comment on it?
Thanks, Pasha
P.S. For the information to be complete <iostream.h> is included in logon macro.
--------------------------------------------------------------------------------
void test1 () {
TStopwatch t;
t.Start();
int k;
for (int i=0; i<100000; i++) {
k = i;
if (k == -1) {
// cout << " oops! " << endl;
}
}
t.Stop();
printf("RealTime=%f seconds, CpuTime=%f seconds\n",t.RealTime(),t.CpuTime());
}
void test2 () {
TStopwatch t;
t.Start();
int k;
for (int i=0; i<100000; i++) {
k = i;
if (k == -1) {
cout << " oops! " << endl;
}
}
t.Stop();
printf("RealTime=%f seconds, CpuTime=%f seconds\n",t.RealTime(),t.CpuTime());
}
--------------------------------------------------------------------------------
root [1] test1()
RealTime=0.230000 seconds, CpuTime=0.240000 seconds
root [2] test2()
RealTime=28.810000 seconds, CpuTime=27.770000 seconds
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