operator-overloading

问题 I created a Fraction class that is has member functions to add, subtract, multiply, and divide between two Fraction Objects along with the required default and copy constructors. For this problem, I must used pointers (cannot use vectors!) because the Fraction objects can only be created if the user chooses to. In short, the pointer declaration and new initialization are in difference scopes. I am trying to also overload the operator=, operator+, operator-, operator*, and operator/ to accept

问题 My class has a private enum whose members are being used to index an array of strings, the output of which is written to an output stream. private: enum supportedMessageTypes(CRITICAL = 0, WARNING, INFORMATION); string messages[3]; //meanwhile, inside the constructor, messages[3] = {"Critical error message", "Warning message", "Information message"}; Since I'm going to be using the enum values around my code a lot, I'd like to be able to overload operator<< to perform a lookup of the enum

问题 This question already has answers here : Overload -> operator to forward member-access through Proxy (3 answers) Overloading member access operators ->, .* (C++) (5 answers) Closed 4 years ago . As per the title, how to overload -> operator in C++? I can't find any documentation. cppreference glosses over it. The Wikipedia page on overloading similarly glosses over it. Operator overloading <-- this SO post again has a '->' shaped hole in it, although one comment gives a hint: operator->() is

问题 This question is unlikely to help any future visitors; it is only relevant to a small geographic area, a specific moment in time, or an extraordinarily narrow situation that is not generally applicable to the worldwide audience of the internet. For help making this question more broadly applicable, visit the help center. Closed 7 years ago . This is my assignment question Create a class with its own operator new. This operator should allocate 5 objects, and on 5th 'run out of memory' and

问题 I have tried to implement own operator and used in map<>, code looks as follows: #include <iostream> #include <map> #include <string> using namespace std; struct keyInfo { string Key1; string Key2; /*bool keyInfo::operator()(keyInfo const& Left,keyInfo const& Right) const{ return ((Left.Key1<Right.Key1)&&(Left.Key2<Right.Key2)); }*/ }; struct LessComparer{ bool operator()(keyInfo const& Left,keyInfo const& Right) const{ return !(Left.Key1==Right.Key1 && Left.Key2==Right.Key2); } }; struct

问题 I am doing operator+ overloading with multiple parameters as below. #include <iostream> using namespace std; class Integer{ int value; public: Integer(int i) {value=i;}; int getValue() { return value;}; friend Integer operator+ (Integer & a, Integer & b){ Integer I (a.value+b.value); return I; }; }; int main() { Integer a(1), b(2), c(3); Integer d = a+b+c; cout<<d.getValue()<<endl; return 0; } It can't be compile and return" no match for operator+". I read and understand the algorithm of

问题 In opencv, I can construct an object of Mat like this: Mat mat = (Mat_<int>(2, 3) << 1, 2, 3, 4, 5, 6); So it's convenient to initialize an instance of Mat_<type> ,and if I have a custom simplified matrix class Mat2D ,in which i will use this pattern, but how to do? Update: I tried to use variable length parameter list, but error C2829: 'operator <<' cannot have a variable parameter list . 回答1: WARNING: DO NOT DO THIS. YOU HAVE BEEN WARNED. You can achieve this using operator overloading, but

问题 In the following example, the author made several comments on the implicit conversion. Can you explain more detail on these comments, which are not very clear to me. Thanks. class String{ explicit String(int n); String(const char *p); } String s1= ‘a’; //error: no implicit char->String conversion void f(String); String g( ) { f(10); // error: no implicit int->String conversion return 10; // error: no implicit int-> String conversion } 回答1: The author is documenting cases in which the compiler

问题 I have a piece of code that is succesfully compiled in VS2008 and fails to compile in VS2013. There is a class Data::CData which is a variant type implementation. It has a conversion operator overloading: template<class T> T& GetValue(); template<class T> const T& GetValue() const; template<class T> operator T&() { return GetValue<T>(); } template<class T> operator const T&() const { return GetValue<T>(); } The code that produces an error is Data::CData Val; Data::PParams Prm = (const Data:

问题 In this article the author chose the return type to be class type http://www.learncpp.com/cpp-tutorial/92-overloading-the-arithmetic-operators/ emphasized text ,Can we just change the return type to return int, because i wanted to do the following , i tried this and it just worked fine , why did the author made the return type class ?? #include <cstdlib> #include <iostream> using namespace std; class Cents // defining new class { private: int m_Cents; int m_Cents2; public: Cents(int Cents=0,