order-of-execution

来源： https://stackoverflow.com/questions/63505019/why-does-this-code-print-1-2-2-and-not-the-expected-3-3-1

来源： https://stackoverflow.com/questions/49414550/defining-element-initialization-order-when-constructing-stdtuple

问题 I was writing a small python script to understand a concept and got another confusion. Here's the code - x = 5 y = 3 class Exp(object): def __init__(self, x, y): self.x = x self.y = y print("In",x, y, self.x, self.y) print("Middle",x,y) print("Out",x,y) Exp(1,2) The output is - Middle 5 3 Out 5 3 In 1 2 1 2 Now, my concept was python interpreter starts reading and executing the code from the first line to last line. It executes the code inside a class only when it is "called", not when it is

问题 Can someone explain what exactly the LeftFirst Boolean Flag is in Abstract Relational Comparison Algorithm in ECMAScript ? I know that there is only one operator < handling all other relational operators like > , >= , <= as mentioned in the ECMAScript specification in Abstract Relational Comparison using the LeftFirst Boolean Flag for, and example: when we write and run an operation like 10 > 5 the LeftFirst Boolean Flag becomes false , and the left operand 10 is moved to the right side where

问题 I want to know if the execution order of expressions in SELECT statement always takes place from left to right . SET @a := 0; SELECT @a AS first, @a := @a + 1 AS second, @a := @a + 1 AS third, @a := @a + 1 AS fourth, @a := @a + 1 AS fifth, @a := @a + 1 AS sixth; Is it guaranteed that the above query will always generate the following output? first second third fourth fifth sixth 0 1 2 3 4 5 回答1: According to the MySQL manual: However, the order of evaluation for expressions involving user

问题 I wonder that can sure order between destruction of global object and atexit in C++ I have a global object and register atexit function like below: static MyClass g_class; void onExit() { // do some destruction } int main() { atexit(onExit); return 0; } I've found onExit() is invoked before MyClass::~MyClass() in Visual Studio 2012 and gcc4.7.2. Am I sure that onExit is always invoked before global object(like g_class ) destruction? I wonder global object register order and atexit register

问题 Does the following program have undefined behavior in C++17 and later? struct A { void f(int) { /* Assume there is no access to *this here */ } }; int main() { auto a = new A; a->f((a->~A(), 0)); } C++17 guarantees that a->f is evaluated to the member function of the A object before the call's argument is evaluated. Therefore the indirection from -> is well-defined. But before the function call is entered, the argument is evaluated and ends the lifetime of the A object (see however the edits

问题 Does the following program have undefined behavior in C++17 and later? struct A { void f(int) { /* Assume there is no access to *this here */ } }; int main() { auto a = new A; a->f((a->~A(), 0)); } C++17 guarantees that a->f is evaluated to the member function of the A object before the call's argument is evaluated. Therefore the indirection from -> is well-defined. But before the function call is entered, the argument is evaluated and ends the lifetime of the A object (see however the edits

问题 I defined two ActionFilters: [DefaultResources(Order = 2)] [RenderTemplate(Order = 1)] And to my surprise DefaultResources is executed BEFORE RenderTemplate. But according to MSDN documentation it should work vice versa: [Filter1(Order = 2)] [Filter2(Order = 3)] [Filter3(Order = 1)] public void Index() { View("Index"); } In this example, action filters would execute in the following order: Filter3, Filter1, and then Filter2. I'm using .NET 4. And comparing by method OnActionExecuted. Am I

问题 How to customize the order of execution of tests in TestNG? For example: public class Test1 { @Test public void test1() { System.out.println("test1"); } @Test public void test2() { System.out.println("test2"); } @Test public void test3() { System.out.println("test3"); } } In the above suite, the order of execution of tests is arbitrary. For one execution the output may be: test1 test3 test2 How do I execute the tests in the order in which they've been written? 回答1: This will work. @Test