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C++ tutorial: operator reference
Operator reference
These tables list the most commonly used C++ operators
Arithmetic operators
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+
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Plus
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-
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Minus
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can be used in 'unary' format, e.g., '-x'
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*
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Multiply
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/
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Divide
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%
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Modulus
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'x % y' is the remainder when x is divided by y
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Bitwise operators
These operate on the individual binary bits in a variable or expression.
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&
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bitwise AND
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'x & y' means the result of the bitwise AND operation applied to x and y
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bitwise OR
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'x | y' means the result of the bitwise OR operation applied to x and y
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^
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bitwise XOR
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'x ^ y' means the result of the bitwise XOR operation applied to x and y
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~
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bitwise NOT
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'~x' means the result of the bitwise NOT operator applied to each of the bits of x
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Assignment operators
These are used to assign values to, or directly modify, the value
of a variable
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=
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equal
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'x = y' means 'set x to the same value as y'
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++
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increment
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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.
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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
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&&
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and
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'x && y' is true if both x and y are true
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||
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or
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'x || y' is true if either x or y is true, or both are
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!
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not
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'!x' is true if either x is not true
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Comparison operators
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==
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Equal
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'x == y' is true if x is equal to y
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!=
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Not equal
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'x != y' is true if x is not equal to y
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