operator-overloading

问题 Is it a bad practice to overload global operator == and != for floating points ? I'm using fast floating-points in a game environement, and i was thinking about using fuzzy comparison everywhere as i can't imagine a situation where i don't expect extremely close numbers not to be equals. Any advice ? 回答1: Other posts mentioned technical problems, from another perspective: Its a bad practice because nobody expects these operators to be overloaded, while reasonable people will expect an

问题 This question already has answers here : Closed 6 years ago . Possible Duplicate: Why do I get “unresolved external symbol” errors when using templates? I am making a linkedList. I am using an external iterator. The Iterator class is a template, and I am implementing my methods in the Iterator.h. Here is the template: #pragma once #include "Node.h" namespace list_1 { template<typename T> class Iterator { public: Iterator<T> (Node<T> *np); void operator++(); bool is_item(); T operator* ();

问题 This post poses the question for the case of !! . The accepted answer tell us that what you are actually doing is creating a new function !! and then you should avoid importing the standard one. But, why to do so if the new function is to be applied to different types than the standard one? Is not the compiler able to choose the right one according to its parameters? Is there any compiler flag to allow this? For instance, if * is not defined for [Float] * Float Why the compiler cries >

问题 This: debug.getmetatable("").__index = function (s, i) return s:sub(i, i) end and this: debug.getmetatable("").__index = _proc_lua_read does not work. 回答1: Try debug.getmetatable("").__index = function (s, i) return string.sub(s,i,i) end Note that by redefining __index for strings in that way, you lose the ability to call methods on strings: note how the code does not call s:sub . For a better solution that avoids that, see http://lua-users.org/lists/lua-l/2007-11/msg00619.html . Or set _

问题 I have a class I created that overloads the "" operator to print out a nice stringified form of the object that is user-readable. But now, I'd like to actually get the memory address such as: Some_class=HASH(0xb0aff98) which is what I would have normally done by using print "$some_object" if I had not already overridden the "" operator. Is there someway to bypass the overridden method or, failing that, just get the memory address of this object? 回答1: Use overload::StrVal($o). use overload '""

问题 I've looked through a lot of questions here for something similar and there are quite a few, albeit with one minor change. I'm trying to sort values with a zip_iterator as a compound key. Specifically, I have the following function: void thrustSort( unsigned int * primaryKey, float * secondaryKey, unsigned int * values, unsigned int numberOfPoints) { thrust::device_ptr dev_ptr_pkey = thrust::device_pointer_cast(primaryKey); thrust::device_ptr dev_ptr_skey = thrust::device_pointer_cast

问题 In particular, the prefix operators' return-by-reference makes sense to me - it's useful, in case one wants to do further operations on the object. However, I can't get my head around why the postfix operator was designed to return by value. Is it solely a convention, or was there a good reason why it was designed this way (like a return-by-value does not make sense for postfix, but makes sense for prefix)? Can someone explain? ANSWER Thanks to the answers below, it appears that the postfix

问题 This question already has answers here : Closed 9 years ago . Possible Duplicate: Java operator overload In c++, we can perform the operator overloading. But Java is also a Object oriented language. So why java doesn't support overloading? 回答1: Actually, it does support operator overloading... of a very limited, built-in only nature. For instance "+" is overloaded for String's in addition to the usual arithmetic. Of course, most people want to know why Java does not support user-defined

问题 I am quite confused about this. How to return a dynamically allocated object from operator function? Consider following example: #include "stdafx.h" #include <iostream> #include "vld.h" using std::cout; class Point { public: Point(int x,int y) : a(x),b(y) { } Point() { } Point operator + (Point p) { Point* temp=new Point(); temp->a=a+p.a; temp->b=b+p.b; Point p1(*temp); // construct p1 from temp delete temp; // deallocate temp return p1; } void show() { cout<<a<<' '<<b<<'\n'; } private: int a

问题 I'd like to write a simple wrapper for the python list type that forces it to start indexing at 1 instead of 0 . I've got a a fairly complex program based on some discrete probability distributions of duration data, with integer-length buckets, but I don't have any durations of less than 1. Anyway, it would greatly simplify a some significant portions of my code to be able to seamlessly index starting at 1. I was using a dict at first but I found several properties of them to be too