Assignment operators

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Assignment operators modify the value of the object.

Operator name	Syntax	Overloadable	Prototype examples (for class T)
Operator name	Syntax	Overloadable	Inside class definition	Outside class definition
basic assignment	`a = b`	Yes	T& T::operator =(const T2 &b);	N/A
move assignment (C++11)	`a = rvalue`	Yes	T& T::operator =(const T2 &&b);	N/A
addition assignment	`a += b`	Yes	T& T::operator +=(const T2 &b);	T& operator +=(T &a, const T2 &b);
subtraction assignment	`a -= b`	Yes	T& T::operator -=(const T2 &b);	T& operator -=(T &a, const T2 &b);
multiplication assignment	`a *= b`	Yes	T& T::operator *=(const T2 &b);	T& operator *=(T &a, const T2 &b);
division assignment	`a /= b`	Yes	T& T::operator /=(const T2 &b);	T& operator /=(T &a, const T2 &b);
modulo assignment	`a %= b`	Yes	T& T::operator %=(const T2 &b);	T& operator %=(T &a, const T2 &b);
bitwise AND assignment	`a &= b`	Yes	T& T::operator &=(const T2 &b);	T& operator &=(T &a, const T2 &b);
bitwise OR assignment	`a \|= b`	Yes	T& T::operator \|=(const T2 &b);	T& operator \|=(T &a, const T2 &b);
bitwise XOR assignment	`a ^= b`	Yes	T& T::operator ^=(const T2 &b);	T& operator ^=(T &a, const T2 &b);
bitwise left shift assignment	`a <<= b`	Yes	T& T::operator <<=(const T2 &b);	T& operator <<=(T &a, const T2 &b);
bitwise right shift assignment	`a >>= b`	Yes	T& T::operator >>=(const T2 &b);	T& operator >>=(T &a, const T2 &b);
Notes All operators usually return `*this`. However, essentially any value and any type can be returned (including void, i.e. no return value), yet this is unintuitive and defeats the purpose of the operators. `T2` can be any type including `T`

[edit] Explanation

basic assignment operator replaces the contents of the object a with those of b

move assignment operator replaces the contents of the object a with those of b while minimizing copying overhead (no deep copy is performed). It complements the basic assignment operator. (C++11 feature)

Other assignment operators modify the contents of the object. Usually they are overloaded in classes performing mathematical operations.

[edit] See also

Operator precedence

Common operators
assignment	increment decrement	arithmetic	logical	comparison	member access	other
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` converts one type to another compatible type `dynamic_cast` converts virtual base class to derived class `const_cast` converts type to compatible type with different cv qualifiers `reinterpret_cast` converts type to incompatible type `new` allocates memory `delete` deallocates memory `sizeof` queries the size of a type `sizeof...` queries the size of a parameter pack (C++11 feature) `typeid` queries the type information of a type `noexcept` checks if an expression can throw an exception (C++11 feature) `alignof` queries alignment requirements of a type (C++11 feature)