I think it is an optimisation! A little known and rarely (you could say “never”) used feature of typeid is that a null dereference of the argument of typeid throws an exception instead of the usual UB. What? Are you serious? Are you drunk? Indeed. Yes. No. int *p = 0; *p; // UB typeid …
Something like Groovy’s null-safe dereferencing operator? string zipCode = customer?.Address?.ZipCode; I gather that the C# team has looked at this and found that it’s not as simple to design elegantly as one might expect… although I haven’t heard about the details of the problems. I don’t believe there’s any such thing in the language at …
This is a fairly frequently asked question. In C#, we almost always reason from inside to outside. When you see x = y; we work out what is the type of x, what is the type of y, and whether the type of y is assignment compatible with x. But we do not use the …
I prefer to think of it as “bitwise vs. conditional” rather than “logical vs conditional” since the general concept of “logical” applies in both cases. x & y // bitwise AND, 0101 & 0011 = 0001 x | y // bitwise OR, 0101 | 0011 = 0111 x && y // true if both x …
To me, the if IS the equivalent of a ternary operator as it evaluates to a value which for various other languages it doesn’t. so x = if false, do: 1, else: 2 is basically x = false? 1 : 2 Not sure why Ruby adopted it ( if you are coming from Ruby ) …
In C, the real utility of it is that it’s an expression instead of a statement; that is, you can have it on the right-hand side (RHS) of a statement. So you can write certain things more concisely.
The problem occurs because the conditional operator doesn’t look at how the value is used (assigned in this case) to determine the type of the expression — just the true/false values. In this case, you have a null and an Int32, and the type can not be determined (there are real reasons it can’t just …
The syntax would be: var icon = (area == 1) ? icon1 : (area == 2) ? icon2 : icon0; But this is starting to get complicated. You may well be better off just creating a function to do this work instead: var icon = getIcon(area); function getIcon(area) { if (area == 1) { return …
In Kotlin, if statements are expressions. So the following code is equivalent: if (a) b else c The distinction between expression and statement is important here. In Java/C#/JavaScript, if forms a statement, meaning that it does not resolve to a value. More concretely, you can’t assign it to a variable. // Valid Kotlin, but invalid …
When your first argument is null, they’re basically the same except that the null coalescing won’t output an E_NOTICE when you have an undefined variable. The PHP 7.0 migration docs has this to say: The null coalescing operator (??) has been added as syntactic sugar for the common case of needing to use a ternary …