operators

问题 I was wondering if there is widely recognized name for === operator. Something like "IIFE" for (function () {})(); 回答1: I was wondering if there is widely recognized name for === operator. The names I've heard most commonly are strict equality operator and strict equals operator . And it turns out that arguably, it has both those names: The old spec called it the strict equals operator: 11.9.4 The Strict Equals Operator ( === ) The production EqualityExpression : EqualityExpression ===

问题 I'm almost sure that not, but I didn't find a difinitive answer to that: Is it possible to overload the curly braces? As in: class Foo { int i; public: int operator{}(int _i){return _i+42;}; }; int main() { Foo f; f{2}; return 0; } It is never mentioned, neither as allowed nor as not allowed. gcc 4.6 doesn't compile it, but that doesn't mean it is not allowed by the standard, right? 回答1: In C++ curly braces {} are not operators unlike the [] (Array subscripting operator) or () (Function call

问题 For example: int a = 10; a += 1.5; This runs perfectly, but a = a+1.5; this assignment says Type mismatch: cannot convert from double to int . So my question is: what is the difference between += operator and = operator . Why the first assignment didn't says nothing, but second will. Please explain to me. Just I want to know whether I can use the first assignment to all place or not. 回答1: From the Java Language Specification section 15.26.2: A compound assignment expression of the form E1 op=

问题 I know about Macro's Stringizing operator ( # ) and I recently learned about the ( ## ) Concatenation operator: Preprocessor Stringizing Operator with String Literal Prefixes Are there any other macro operators that are available to me? I know that Boost has a pretty extensive suite that they've put together, however for the purposes of this question I'm just asking about Macro operator support defined by the standard. 回答1: As is mentioned by Cyber's comment the Sringizing ( # ) and

问题 I know about Macro's Stringizing operator ( # ) and I recently learned about the ( ## ) Concatenation operator: Preprocessor Stringizing Operator with String Literal Prefixes Are there any other macro operators that are available to me? I know that Boost has a pretty extensive suite that they've put together, however for the purposes of this question I'm just asking about Macro operator support defined by the standard. 回答1: As is mentioned by Cyber's comment the Sringizing ( # ) and

问题 I know about Macro's Stringizing operator ( # ) and I recently learned about the ( ## ) Concatenation operator: Preprocessor Stringizing Operator with String Literal Prefixes Are there any other macro operators that are available to me? I know that Boost has a pretty extensive suite that they've put together, however for the purposes of this question I'm just asking about Macro operator support defined by the standard. 回答1: As is mentioned by Cyber's comment the Sringizing ( # ) and

问题 I have this statement: return *local_stack_var2++ + 42; Would these be the proper steps when breaking it down: 1. Dereference local_stack_var2 2. Add 42 to the dereferenced local_stack_var2 (function will actually return this value) 3. Before the function is over, it will activate the post-increment, incrementing the value of the object pointed to by local_stack_var2 So in code format, it would look kind of something like this? int temp = *local_stack_var2 //step 1; int returnValue = temp +

问题 I would want to make a template of a << operator in C++, that would show a Object that is a "range" (by that i mean any object like : std::vector, std::set, std::map, std::deque). How can i achieve this? I've been googling and looking in docs for a few days now, but without any effect. I've been doing few templates and been overriding few operators before, but these were inside of a certain class that was representing a custom vector class. I cant seem to find a good way of implementing this,

问题 I would want to make a template of a << operator in C++, that would show a Object that is a "range" (by that i mean any object like : std::vector, std::set, std::map, std::deque). How can i achieve this? I've been googling and looking in docs for a few days now, but without any effect. I've been doing few templates and been overriding few operators before, but these were inside of a certain class that was representing a custom vector class. I cant seem to find a good way of implementing this,

问题 What does the &= operator mean in Python, and can you give me a working example? I am trying to understand the __iand__ operator. I just don't know what &= means and have looked online but couldn't find it. 回答1: Explanation Understandable that you can't find much reference on it. I find it hard to get references on this too, but they exist. The i in iand means in-place , so it's the in-place operator for & . &= calls the __iand__ operator, if it is implemented. If not implemented, it is the