C# provides a large set of operators, which are symbols that specify which operations to perform in an expression. C# predefines the usual arithmetic and logical operators, as well as a variety of others as shown in the following table. In addition, many operators can be overloaded by the user, thus changing their meaning when applied to a user-defined type.

Arithmetic Overflow

The arithmetic operators (+, -, *, /) can produce results that are outside the range of possible values for the numeric type involved. You should refer to the C# Language Reference section on a particular operator for details, but in general:

• Integer arithmetic overflow either throws an OverflowException or discards the most significant bits of the result (see below). Integer division by zero always throws a DivideByZeroException.
• Floating-point arithmetic overflow or division by zero never throws an exception, because floating-point types are based on IEEE 754 and so have provisions for representing infinity and NaN (Not a Number).
• Decimal arithmetic overflow always throws an OverflowException. Decimal division by zero always throws a DivideByZeroException.

When integer overflow occurs, what happens depends on the execution context, which can be checked or unchecked. In a checked context, an OverflowException is thrown. In an unchecked context, the most significant bits of the result are discarded and execution continues. Thus, C# gives you the choice of handling or ignoring overflow.

In addition to the arithmetic operators, integral-type to integral-type casts can cause overflow (for example, casting a long to an int) and are subject to checked or unchecked execution. Also note that bitwise operators and shift operators never cause overflow.

See Also

7.2.1 Operator precedence and associativity | Overloadable Operators | C# Keywords | C# Programmer's Reference