Increment/decrement operators

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Increment/decrement operators increments or decrements the value of the object.

Operator name	Syntax	Overloadable	Prototype examples (for class T)
Operator name	Syntax	Overloadable	Inside class definition	Outside class definition
pre-increment	`++a`	Yes	T& T::operator++();	T& operator++(const T &a);
pre-decrement	`--a`	Yes	T& T::operator--();	T& operator--(const T &a);
post-increment	`a++`	Yes	T& T::operator++(int);	T& operator++(const T &a, int);
post-decrement	`a--`	Yes	T& T::operator--(int);	T& operator--(const T &a, int);
Notes All operators usually return a value of type T. However, essentially any type can be returned (including void, i.e. no return value), yet this is unintuitive and thus defeats the purpose of the operators. The int parameter is a dummy parameter used to differentiate between pre- and post- in versions of the operators.

[edit] Explanation

pre-increment and pre-decrement operators increments or decrements the value of the object and returns the resulting value.

post-increment and post-decrement operators increments or decrements the value of the object and returns the value of the object before the operation. Because a temporary copy of the object is made during the operation, for efficiency reasons it is better to employ pre-increment or pre-decrement operators in contexts where the returned value is not used.

[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 (since C++11) `typeid` queries the type information of a type `noexcept` checks if an expression can throw an exception (since C++11) `alignof` queries alignment requirements of a type (since C++11)