Re: min and max running values

From:
Pete Becker <pete@versatilecoding.com>
Newsgroups:
comp.lang.c++
Date:
Mon, 05 Mar 2007 20:33:30 -0500
Message-ID:
<_fudnfGPB55wWXHYnZ2dnUVZ_tOmnZ2d@giganews.com>
Clark Cox wrote:

On 2007-03-05 15:31:29 -0800, Pete Becker <pete@versatilecoding.com> said:

Gary Wessle wrote:

Hi

often I need to read numbers and only keep the highest or lowest.
so I do something like
int uLimit = 0;
int lLimit = 999999999999; //hoping the compiler will not complain

uLimit = val_read > uLimit ? val_read : uLimit;
lLimit = val_read < lLimit ? val_read : lLimit;

how do I choose the original lLimit?


Use the first value of val_read for both limits.


I would tend to disagree, as that would require a special case for the
first iteration of the loop.

i.e. I would prefer A to B:


Err, they do two different things. And, of course, they're written to
make A look better.

/*A*/
int maxValue = std::numeric_limits<int>::min();
int minValue = std::numeric_limits<int>::max();

while( ... )
{
 int input = getNextValue();
 maxValue = std::max(maxValue, input);
 minValue = std::min(minValue, input);

 ...
}

/*B*/
int input = getNextValue();
int maxValue = input;
int minValue = input;

do
{
 input = getNextValue();
 maxValue = std::max(maxValue, input);
 minValue = std::min(minValue, input);
}
while(...);


Let me present two versions that are biased the other way:

/*A*/
maxValue = std::numeric_limits<int>::min();
minValue = std::numeric_limits<int>::max();

while (...)
{
int input = getNextValue();
maxValue = std::max(maxValue, input);
minValue = std::min(minValue, input);
....
}

/*B*/
maxValue = minValue = getNextValue();

while (...)
{
int input = getNextValue();
maxValue = std::max(maxValue, input);
minValue = std::min(minValue, input);
....
}

Obviously B is vastly superior to the wordy, verbose, lengthy,
overwrought, wordy, redundant, and repetitive A. <g>

--

    -- Pete
Roundhouse Consulting, Ltd. (www.versatilecoding.com)
Author of "The Standard C++ Library Extensions: a Tutorial and
Reference." (www.petebecker.com/tr1book)

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