C++ tutorial: operator reference

Operator reference
These tables list the most commonly used C++ operators

Arithmetic operators

+ Plus

- Minus can be used in 'unary' format, e.g., '-x'

* Multiply

/ Divide

% Modulus 'x % y' is the remainder when x is divided by y

Bitwise operators
These operate on the individual binary bits in a variable or expression.

& bitwise AND 'x & y' means the result of the bitwise AND operation applied to x and y

| bitwise OR 'x | y' means the result of the bitwise OR operation applied to x and y

^ bitwise XOR 'x ^ y' means the result of the bitwise XOR operation applied to x and y

~ bitwise NOT '~x' means the result of the bitwise NOT operator applied to each of the bits of x

Assignment operators
These are used to assign values to, or directly modify, the value of a variable

= equal 'x = y' means 'set x to the same value as y'

++ increment If ++ is applied to a number variable, it simply adds one to the variable's value. There are two alternative representations: x++ (called 'post-increment') and ++x (called pre-increment). If 'x++' is a statement on its own pre- and post-increment instructions have exactly the same effect. If 'x++' is part of a larger expression being evaluated, pre-increment cause the value to be incremented before the expression is evaluated, while post-increment causes the increment to come after evaluation. In my opinion, a program is easier to understand if it is written in such a way that pre-increment and post-increment would be identical. This saves the reader needing to work out the order in whcih things happen.

Note that all the arithmetic and bitwise operators can also be assignement operators, simply by appending the '=' sign to the symbol. For example, 'x += 2' means 'add two to x'. '+=' is usually read "plus and becomes". However, the use of these symbols, while often very concise, can cause difficulty for a person trying to understand the program; use with caution.

Logical operators

&& and 'x && y' is true if both x and y are true

|| or 'x || y' is true if either x or y is true, or both are

! not '!x' is true if either x is not true

Comparison operators

== Equal 'x == y' is true if x is equal to y

!= Not equal 'x != y' is true if x is not equal to y

+	Plus
-	Minus	can be used in 'unary' format, e.g., '-x'
*	Multiply
/	Divide
%	Modulus	'x % y' is the remainder when x is divided by y

&	bitwise AND	'x & y' means the result of the bitwise AND operation applied to x and y
\|	bitwise OR	'x \| y' means the result of the bitwise OR operation applied to x and y
^	bitwise XOR	'x ^ y' means the result of the bitwise XOR operation applied to x and y
~	bitwise NOT	'~x' means the result of the bitwise NOT operator applied to each of the bits of x

=	equal	'x = y' means 'set x to the same value as y'
++	increment	If ++ is applied to a number variable, it simply adds one to the variable's value. There are two alternative representations: x++ (called 'post-increment') and ++x (called pre-increment). If 'x++' is a statement on its own pre- and post-increment instructions have exactly the same effect. If 'x++' is part of a larger expression being evaluated, pre-increment cause the value to be incremented before the expression is evaluated, while post-increment causes the increment to come after evaluation. In my opinion, a program is easier to understand if it is written in such a way that pre-increment and post-increment would be identical. This saves the reader needing to work out the order in whcih things happen.

&&	and	'x && y' is true if both x and y are true
\|\|	or	'x \|\| y' is true if either x or y is true, or both are
!	not	'!x' is true if either x is not true

==	Equal	'x == y' is true if x is equal to y
!=	Not equal	'x != y' is true if x is not equal to y