operator-keyword

问题 Product **products; int numProducts = 0; void setup() { ifstream finput("products.txt"); //get # of products first. finput >> numProducts; products = new Product* [numProducts]; //get product codes, names & prices. for(int i=0; i<numProducts; i++) { products[i] = new Product; finput >> products[i]->getCode() >> products[i]->getName() >> products[i]->getPrice(); } } I am getting an "invalid operands to binary expression" error for this line: finput >> products[i]->getCode() >> products[i]-

问题 Product **products; int numProducts = 0; void setup() { ifstream finput("products.txt"); //get # of products first. finput >> numProducts; products = new Product* [numProducts]; //get product codes, names & prices. for(int i=0; i<numProducts; i++) { products[i] = new Product; finput >> products[i]->getCode() >> products[i]->getName() >> products[i]->getPrice(); } } I am getting an "invalid operands to binary expression" error for this line: finput >> products[i]->getCode() >> products[i]-

问题 I just found this: sed '/label/{n;n;s/{}/{some comment}/;}' The intended effect is to seek label , proceed 2 lines down ( n;n; ) then substitute in ( s ) some comment . This is an amazing capability I never knew sed had. Would someone be kind enough to specify the name of this curly brace notation, and the name of the class of operators inside the braces? 回答1: Curly brackets allow to group several commands so that they are executed for the same address range (reference). The thing here is

问题 I just found this: sed '/label/{n;n;s/{}/{some comment}/;}' The intended effect is to seek label , proceed 2 lines down ( n;n; ) then substitute in ( s ) some comment . This is an amazing capability I never knew sed had. Would someone be kind enough to specify the name of this curly brace notation, and the name of the class of operators inside the braces? 回答1: Curly brackets allow to group several commands so that they are executed for the same address range (reference). The thing here is

问题 The increase assignment operator ( += ) is often used in [PowerShell] questions and answers at the StackOverflow site to construct a collection objects, e.g.: $Collection = @() 1..$Size | ForEach-Object { $Collection += [PSCustomObject]@{Index = $_; Name = "Name$_"} } Yet it appears an very inefficient operation. Is it Ok to generally state that the increase assignment operator ( += ) should be avoided for building an object collection in PowerShell? 回答1: Yes, the increase assignment operator

问题 As it currently stands, this question is not a good fit for our Q&A format. We expect answers to be supported by facts, references, or expertise, but this question will likely solicit debate, arguments, polling, or extended discussion. If you feel that this question can be improved and possibly reopened, visit the help center for guidance. Closed 8 years ago . I have a question about the this operator in Java. In the case where a programmer would write a code like this: private int counter;

问题 As it currently stands, this question is not a good fit for our Q&A format. We expect answers to be supported by facts, references, or expertise, but this question will likely solicit debate, arguments, polling, or extended discussion. If you feel that this question can be improved and possibly reopened, visit the help center for guidance. Closed 8 years ago . I have a question about the this operator in Java. In the case where a programmer would write a code like this: private int counter;

问题 This question already has answers here : PHP ternary operator vs null coalescing operator (13 answers) Closed 2 years ago . I was diving into Symfony framework (version 4) code and found this peace of code: $env = $_SERVER['APP_ENV'] ?? 'dev'; I'm not pretty sure what this actually does but I imagine that it expands to something like: $env = $_SERVER['APP_ENV'] != null ? $_SERVER['APP_ENV'] : 'dev'; Or maybe: $env = isset($_SERVER['APP_ENV']) ? $_SERVER['APP_ENV'] : 'dev'; Someone has any

问题 Im having trouble figuring out how to implement the equivalent of overloading the assignment operator in C++ to Java. I know there is no such thing, but I need to simulate it. I've tried overriding the Clone() function, but no luck. Any ideas? Below is my main Queue p = new Queue(); Queue q = new Queue(); p.enqueue('a'); p.enqueue(9); p.enqueue(10); p.enqueue(310); p.enqueue(8); q = p; System.out.print(p); And here is the clone function public void Clone(Queue other) throws Throwable { System

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