short-circuiting

VB has operators AndAlso and OrElse , that perform short-circuiting logical conjunction. Why is this not the default behavior of And and Or expressions since short-circuiting is useful in every case. Strangely, this is contrary to most languages where && and || perform short-circuiting. Because the VB team had to maintain backward-compatibility with older code (and programmers!) If short-circuiting was the default behavior, bitwise operations would get incorrectly interpreted by the compiler. Why did we introduce AndAlso and OrElse? by Panopticon Central Our first thought was that logical

Say I have this code: unsigned int func1(); unsigned int func2(); unsigned int func3(); unsigned int x = func1() | func2() | func3(); Does C++ guarantee that func1() will be called first, then func2(), and then func3()? Or is the compiler allowed to call the functions in any order it feels like? Also, is the compiler allowed to implement a short-circuit optimization here if it wants to? (e.g. if func1() returned ~0, could the compiler decide not to bother calling func2() or func3(), because it knows their return values can't possibly affect the value assigned to x?) No, there is no guarantee

I have executed the following code in Code::Blocks 10.05 on Windows 7. int a=0,b=0,c; c=a++&&b++; printf("\na=%d\nb=%d\nc=%d\n\n",a,b,c); The output I obtained is given below, a=1 b=0 c=0 This makes perfect sense because of short circuit evaluation. The expression a++ is post increment and 0 is returned to the logical and ( && ). Hence the part b++ is not evaluated since both 0 && 0 and 0 && 1 evaluates to 0 . But here arises my doubt. The precedence value of operators clearly states that ++ is having higher precedence over && . So my understanding was like this, both a++ and b++ are evaluated

I thought Java had short circuit evaluation, yet this line is still throwing a null pointer exception: if( (perfectAgent != null) && (perfectAgent.getAddress().equals(entry.getKey())) ) { In this case perfectAgent is null , so I just want the whole expression to return false , but my app is still crashing on this line with a NullPointerException. EDIT, general response: Since perfectAgent is null , nothing to the right of the && should be executed, as it is impossible for the expression to be true. More to the point, it is impossible to execute perfectAgent.getAddress() since perfectAgent does

I'm new to Haskell, and I'm trying a bit: isPrime :: Integer->Bool isPrime x = ([] == [y | y<-[2..floor (sqrt x)], mod x y == 0]) I have a few questions. Why when I try to load the .hs, WinHugs say: Instances of (Floating Integer, RealFrac Integer) required for definition of isPrime ? When the interpreter finds one element in the right set, it immediately stops or it computes all the set? I think you know what I mean. Sorry about my english. 1) The problem is that sqrt has the type (Floating a) => a -> a , but you try to use an Integer as argument. So you have to convert your Integer first to

Recently came across short-circuit evaluation and was a little confused by it as i only got into programming the past week. From what i understand if what ever comes before the first double pipe is true then it will stop and not evaluate what comes after the double pipe. For Example: Example 1: var a = true; var b = a || {}; So i assume if a exists then assign a to b otherwise b is equal to an object. What i dont understand is where i will use this and how it differs to a ternary operator, isn't the short circuit evaluation the same as: Example 2: var a = true; var b = (a) ? a : {}; Why would