When an expression contains multiple operators, the precedence of the operators controls the order in which the individual operators are evaluated. When the operators are of the same precedence, their associativity determines their order of evaluation. Binary operators (except for assignment operators) are left-associative and are evaluated from left to right. The assignment operators, unary operators, and the conditional operator are right-associative , evaluated from right to left.

For example:

1 + 2 + 3 * 4

is evaluated as:

((1 + 2) +(3 * 4))

because * has a higher precedence than +, and + is a left-associative binary operator. You can insert brackets to change the default order of evaluation. C# also overloads operators, which means the same operator symbols can have different meanings in different contexts (e.g., primary, unary, etc.) or different meanings for different types.

Table 2.2 lists C#’s operators in order of precedence. Operators in the same box have the same precedence, and operators in italic may be overloaded for custom types (see Section 2.9.8).

Checked/unchecked operators:

Checked/unchecked statements:

The checked operator tells the runtime to generate an OverflowException if an integral expression exceeds the arithmetic limits of that type. The checked operator affects expressions with the ++, --, (unary)-, +, -, *, /, and explicit conversion operators ( ) between integral types (see Section 2.2.5.1). Here’s an example:

int a = 1000000;
int b = 1000000;

// Check an expression
int c = checked(a*b);

// Check every expression in a statement-block
checked {
   ...
   c = a * b;
   ...
}

The checked operator applies only to runtime expressions, because constant expressions are checked during compilation (though this can be turned off with the /checked [+|-] command-line compiler switch). The unchecked operator disables arithmetic checking at compile time and is seldom useful, but it can enable expressions such as this to compile:

const int signedBit = unchecked((int)0x80000000);