C# allows user-defined types to overload operators by defining static member functions using the operator keyword. Not all operators can be overloaded.

These unary operators can be overloaded : +, -, !, ~, ++, --, true, false

These binary operators can be overloaded : +, -, *, /, %, &, |, ^, <<, >>

The comparison operators can be overloaded : ==, !=, <, >, <=, >=

The conditional logical operators cannot be overloaded, but they are evaluated using & and |, which can be overloaded : &&, ||

The array indexing operator cannot be overloaded, but you can define indexers: [ ]

The cast operator cannot be overloaded, but you can define new conversion operators :( )

Assignment operators cannot be overloaded, but +=, for example, is evaluated using +, which can be overloaded : +=, -=, *=, /=, %=, &=, |=, ^=, <<=, >>=

These operators cannot be overloaded : =, ., ?:, ->, new, is, sizeof, typeof

In C#, an operator is a term or a symbol that takes one or more expressions, called operands, as input and returns a value. Operators that take one operand, such as the increment operator (++) or new, are called unary operators. Operators that take two operands, such as arithmetic operators (+,-,*,/) are called binary operators. One operator, the conditional operator (?:), takes three operands and is the sole tertiary operator in C#.

Primary:

x.y, f(x), a[x], x++, x--, new, typeof, checked, unchecked

Unary:

+, -, !, ~, ++x, --x, (T)x

Arithmetic — Multiplicative:

*, /, %

Arithmetic — Additive:

+, -

Shift:

<<, >>

Relational and type testing:

<, >, <=, >=, is, as

Equality:

==, !=

Logical, in order of precedence :

&, ^, |

Conditional, in order of precedence:

&&, ||, ?:

Assignment:

=, +=, -=, *=, /=, %=, &=, |=, ^=, <<=, >>=