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C++ operators

Arithmetic operators

operator	name
+	addition
-	substraction
*	multiplication
/	division
%	modulus

operator	name	example	description
++x	pre-increment	++5	first increment x then return x
–x	pre-decrement	–5	first decrement x then return x
x++	post-increment	5++	first copy x then increment x then return copy
x–	post-decrement	5–	first copy x then decrement x then return copy

Pre vs post-increment/decrement

When place before the operand, it is a pre-increment/decrement operator.

1. The value of the operand is incremented/decremented
2. The new operand value is returned.

int x = 10;

// x is decremented to 9, then assigned to y
int y = --x;

std::cout << x << ' ' << y;

//output: 9 9

When place after the operand, it is a post-increment/decrement operator.

1. The value of the operand is copied
2. The operand (not the copy) is incremented/decremented
3. The copy (not the original value) is retured

int x = 10;

// a copy of x is made, x is decremented to 9
// the value of the copy (10) is assigned to y
int y = x--;

std::cout << x << ' ' << y;

//output: 9 10

Assignment operators

Operators that assign value to a variable.

operator	example
=	x = 5
+=	x += 5
-=	x -= 5
*=	x *= 5
/=	x /= 5
%=	x %= 5

Relational operators

Compare two variables or values.

The result of the operation is a bool.

operator	example
==	x == y
!=	x != y
>	x > y
<	x < y
>=	x > y
<=	x < y

Logical operators

Compare the logic of two or more conditions.

The result of the logical operation is a bool.

operator	example
&&	x == y
∣∣	x ∣∣ y
!	!x

Special operator

operator	name	action	exemple
«	insertion		std::cout « “hello”
»	extraction		std::cin » x
::	scope resolution	identifies on the left, the namespace of the right identifier	std::cout

std::cout << "hello there" << name;
std::cin >> variable_name;

Bitwise operators

Manipulate variables at bit level.

Commonly used with numerical variables.

operator	name	example	description
«	left shift	x « y	shift bits in x left by y
»	right shift	x » y	shifht bits in x right by y
~	bitwise NOT	~x	flip all bits in x
&	bitwise AND	x % y	each bit in x AND each bit in y
∣	bitwise OR	x ∣ y	each bit in x OR each bit in y
^	bitwise XOR	x ^ y	each bit in x XOR each bit in y

More info

Operator precedence

In a compound expression, operators are evaluated in the order of their precedence level in descending order (smallest precedence value go first).

Find the complete list here.