operator-keyword

问题 (Using Python 2.7) I understand this is pretty elementary but why wouldn't the following statement work as written: input = int(raw_input()) while input != 10 or input != 20: print 'Incorrect value, try again' bet = int(raw_input()) Basically I only want to accept 10 or 20 as an answer. Now, regardless of 'input', even 10, or 20, I get 'Incorrect value'. Are these clauses self conflicting? I thought that the OR statement would say OK as long as one of the clauses was correct. Thanks! 回答1: You

问题 (Using Python 2.7) I understand this is pretty elementary but why wouldn't the following statement work as written: input = int(raw_input()) while input != 10 or input != 20: print 'Incorrect value, try again' bet = int(raw_input()) Basically I only want to accept 10 or 20 as an answer. Now, regardless of 'input', even 10, or 20, I get 'Incorrect value'. Are these clauses self conflicting? I thought that the OR statement would say OK as long as one of the clauses was correct. Thanks! 回答1: You

问题 This question already has answers here : Is there a difference between x++ and ++x in java? (16 answers) Pre & post increment operator behavior in C, C++, Java, & C# [duplicate] (6 answers) Closed 4 years ago . Can someone explain the implementation of the following code: int j = 1; System.out.println(j-- + (++j / j++)); I'm expecting the output to be 3 as explained below: Since '/' has higher precedence than '+' it is evaluated first. op1 = ++j (Since it is pre-increment, the value is 2, and

问题 I am currently working on a concept of Object known in Java or C# for C++. It would be similar to variant type like boost::any, however having wider functionality. For that purpose I am using boost::shared_ptr to internaly store actual data and I wanted to provide Return Type Resolver idiom for easily obtaining this data, as it is stored in actual implementation. I know I could use boost::shared_ptr automatic conversion during assigment operator or constructor but as I said shared_ptr is not

问题 I have a 2D array and I want to define a function that returns the value of the index that the user gives me using operator overloading. In other words: void MyMatrix::ReturnValue() { int row = 0, col = 0; cout << "Return Value From the last Matrix" << endl; cout << "----------------------------------" << endl; cout << "Please Enter the index: [" << row << "][" << col << "] =" << ((*this).matrix)[row][col] << endl; } The operation ((*this).matrix)[row][col] should return an int . I have no

问题 I am writing a C# class that is exposed to VB.Net. I would like to overload the vb.net ^ operator so that I can write: Dim c as MyClass Set c = New ... Dim d as MyClass Set d = c^2 In C#, the ^ operator is the xor operator and the power operator doesn't exist. Is there a way I can do this anyway? 回答1: EDIT It turns out there's a SpecialNameAttribute that lets you declare "special" functions in C# that will allow you (among other things) to overload the VB power operator: public class

问题 This question already has answers here : Does Python support short-circuiting? (3 answers) Closed 5 years ago . I get following output with and operator code >>>0 and [] 0 >>>[] and 0 [] >>> 0 and '' 0 >>>'' and 0 '' I could not figure out about on what basis I m getting different result on the basis of placing of elements.. 回答1: From the docs on and : The expression x and y first evaluates x; if x is false, its value is returned; otherwise, y is evaluated and the resulting value is returned.

问题 This question already has answers here : How could comma separated initialization such as in Eigen be possibly implemented in C++? (3 answers) Closed last year . I just want to know if we can give two or more parameters to an overload of operator << An example will be more explicit: anyType operator<<(arg p1, arg p2) { DoSomethingWith(p1); DoSomethingWith(p2); return (*this); } And use it like this: anyVar << anyVar2, anyVar3; 回答1: No, that is not possible. The closest you can come would be

问题 I was wondering if it is good practice to use the member operator . like this: someVector = (segment.getFirst() - segment.getSecond()).normalize().normalCCW(); Just made that to show the two different things I was wondering, namely if using (expressions).member/function() and foo.getBar().getmoreBar() were in keeping with the spirit of readability and maintainability. In all the c++ code and books I learned from, I've never seen it used in this way, yet its intoxicatingly easy to use it as

问题 I need to determine what is the equivalent for SQLite of the <=> operator in MySQL. Any idea? 回答1: The IS and IS NOT operators work like = and != except when one or both of the operands are NULL. In this case, if both operands are NULL, then the IS operator evaluates to 1 (true) and the IS NOT operator evaluates to 0 (false) http://www.sqlite.org/lang_expr.html#isisnot 回答2: I have just found the "IS" operator, but not sure if it has exactly the same behaviour? 来源： https://stackoverflow.com