Hi,
Normally we check a value by this format
if ( obj == null )
{
//do some code
}
I know it is good for readability.
But for performance reason I am suggested by one of my coleagues that
we shuold check the constant value first i.e.
if ( null == obj )
{
//do some code
}
What is the best possible way to check the object
Could any body give the proper reason to use the later one.
What should be the best practice to check the object ?
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What should be the best practice to check the object ?
Henk vd Geld
What do you mean clear you
Rob S
It is not really for performance but to catch bugs like
Boolean bSomething = false;
if (bSomething = true)
{
...this code will execute
}
at compile time instead of maybe when debugging. It is a recommendation to always write constants on the left side of == when comparing with equality operator. The performance increase is in less possible bugs to debug!
if (true = bSomething) // will not even compile
EDIT: To be clear, it is to catch types where you type = instead of ==
ZeeGee
your coleagues seem to be wrong :)
here the result of my little test :)
Left u have (obj == null)
right u have (null == obj)
There are the time results for 1.000.000.000 checks
Object not null
0: 00:00:06.6562500 - 00:00:06.8125000
1: 00:00:06.7343750 - 00:00:06.8281250
2: 00:00:06.7500000 - 00:00:06.5312500
3: 00:00:06.6093750 - 00:00:06.5937500
4: 00:00:06.9687500 - 00:00:06.6250000
5: 00:00:06.5781250 - 00:00:06.8750000
6: 00:00:06.6250000 - 00:00:06.7968750
7: 00:00:06.7343750 - 00:00:06.5156250
8: 00:00:06.5468750 - 00:00:06.5156250
9: 00:00:06.9218750 - 00:00:06.6093750
Object is null
0: 00:00:07.0468750 - 00:00:07.3593750
1: 00:00:07.1250000 - 00:00:07.4531250
2: 00:00:07.0000000 - 00:00:06.9843750
3: 00:00:07.0156250 - 00:00:07.1093750
4: 00:00:07.2656250 - 00:00:07.0312500
5: 00:00:07.2500000 - 00:00:07.2031250
6: 00:00:07.2812500 - 00:00:07.1718750
7: 00:00:06.9843750 - 00:00:07.0000000
8: 00:00:07.0000000 - 00:00:07.4687500
9: 00:00:07.0625000 - 00:00:07.0781250
Martin R
Not sure if ther is any difference ...
only 1 way to know ... just run a test :)
Rod A.
OK
Thanks