The C# Programming Language, Third Edition

7.6.2 Unary Minus Operator

For an operation of the form -x, unary operator overload resolution (§7.2.3) is applied to select a specific operator implementation. The operand is converted to the parameter type of the selected operator, and the type of the result is the return type of the operator. The predefined negation operators are given here:

•  Integer negation:

     int operator -(int x);     long operator -(long x);

   The result is computed by subtracting x from zero. If the value of x is the smallest representable value of the operand type (−2³¹ for int or −2⁶³ for long), then the mathematical negation of x is not representable within the operand type. If this occurs within a checked context, a System.OverflowException is thrown; if it ...