c# Assignment operator &=
if I have the following bool:
开发者_JAVA百科bool success = true;
Will the following three lines of code store the same results in success:
1 - success &= SomeFunctionReturningABool();
2 - success = success & SomeFunctionReturningABool();
3 - success = success && SomeFunctionReturningABool();
I found an article stating that 1 is a shortcut for 2 - but is 2 the same as 3 or is my application going to explode on execution of this line...
For boolean type, single &
evaluates all operands, while double &&
only evaluates while necessary (i.e. if the first operand is false, it won't bother to evaluate the second one), also known as "short-circuit" evaluation.
Source: http://msdn.microsoft.com/en-us/library/2a723cdk(v=vs.80).aspx
As for the &=
assignment operator, it works same as single &
.
1 and 2 are the same in the same way that the following are the same:
int value += 1;
int value = value + 1;
3 is not the same, as if success
is false, SomeFunctionReturningABool()
won't get called - which is not what you want.
You are right. 1 is a shortcut to 2. The difference between '&' and '&&' you can find here msdn
'&' is a logical AND while '&&' is conditional AND
Options 2 and 3 are equivalent, and &=
does exactly that.
You should know that if the first call fails, the subsequent calls might not occur: for example,
if (x != null && x.Test() == true)
It evaluates x != null
first - and if it's false then the second part won't get executed. The same may apply here.
(Huh, I wonder if that's just for && and not &...)
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