operators - cppreference.com

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L'overload degli operatori

Sintassi


type `operator` op `(` params `) ;`

Spiegazione

<tipo> è / sono il tipo (s) delle variabili.
Original:
<type> is/are the type(s) of the variables.
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<op> è l'operatore particolare (ad esempio +, +=, <<, >>, &&, ||, %, ecc).
Original:
<op> is the particular operator (e.g. +, +=, <<, >>, &&, ||, %, etc.).
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<params> è / sono il nome (s) i parametri necessari (dipende dal gestore).
Original:
<params> is/are the name(s) of the required parameters (depends on the operator).
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Restrizioni

Non è possibile creare nuovi operatori come ** o &|.
Original:
You cannot create new operators such as ** or &|.
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Non tutti gli operatori possono essere sottoposti a overload
Original:
Not all operators can be overloaded
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Alcuni operatori possono essere sottoposti a overload come membri non statici della classe
Original:
Some operators can only be overloaded as non-static class members
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Corto circuito di valutazione non funziona con operatori in overload
Original:
Short-circuit evaluation doesn't work with overloaded operators
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Operatore Chiamate

Operatori di overload può essere chiamato con la notazione infissa solito

Original:

Overloaded operators can be called using the usual infix notation

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o di una funzione-notazione

Original:

or a function-like notation

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Esempio

#include <iostream>
 using namespace std;
 
 class Fraction{
   private:
     int numerator, denominator;
     
   public:
     Fraction(int n, int d): numerator(n), denominator(d) {}
   // Note that the keyword operator combined with an actual
   // operator is used as the function name
   friend ostream& operator<<(ostream&, Fraction&);
 };
 
 ostream& operator<<(ostream& out, Fraction& f){
   out << f.numerator << '/' << f.denominator;
   return out;
 }
 
 int main(){
   Fraction f1(3, 8);
   Fraction f2(1, 2);
   
   cout << f1 << endl;
   cout << 3 << ' ' << f2 << endl;
   
   return 0;
 }

Output:

Vedere anche

Common operators
assegnazione	incrementǊdecrement	aritmetica	logico	confronto	memberǊaccess	altra
`a = b a = rvalue a += b a -= b a *= b a /= b a %= b a &= b a \|= b a ^= b a <<= b a >>= b`	`++a --a a++ a--`	`+a -a a + b a - b a * b a / b a % b ~a a & b a \| b a ^ b a << b a >> b`	`!a a && b a \|\| b`	`a == b a != b a < b a > b a <= b a >= b`	`a[b] a &a a->b a.b a->b a.*b`	`a(...) a, b (type) a ? :`
Special operators
`static_cast` converte un tipo a un altro tipo compatibile Original: `static_cast` converts one type to another compatible type The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. `dynamic_cast` converte classe virtuale di base per class derivato Original: `dynamic_cast` converts virtual base class to derived class The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. `const_cast` converte il tipo di tipo compatibile con diversi cv qualifiers Original: `const_cast` converts type to compatible type with different cv qualifiers The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. `reinterpret_cast` converte tipo type incompatibile Original: `reinterpret_cast` converts type to incompatible type The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. `new` alloca memory Original: `new` allocates memory The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. `delete` dealloca memory Original: `delete` deallocates memory The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. `sizeof` interroga la dimensione di un type Original: `sizeof` queries the size of a type The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. `sizeof...` interroga le dimensioni di un parametro confezione (dal C++11) Original: `sizeof...` queries the size of a parametro confezione (dal C++11) The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. `typeid` interroga le informazioni sul tipo di una type Original: `typeid` queries the type information of a type The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. `noexcept` controlla se un'espressione può lanciare una (dal C++11) un'eccezione Original: `noexcept` checks if an expression can throw an exception (dal C++11) The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. `alignof` query requisiti di allineamento di un (dal C++11) tipo Original: `alignof` queries alignment requirements of a type (dal C++11) The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.