int x, y; x = y = int.MaxValue; int result = x + y;
const int x = int.MaxValue; const int y = int.MaxValue; int result = x + y;
int result = unchecked(x + y);
从C#5规范第7.6.12节 – 上市后, – ,/和*：
When one of the above operations produce a result that is too large to represent in the destination type, the context in which the operation is performed controls the resulting behavior:
- In a
checkedcontext, if the operation is a constant expression (§7.19), a compile-time error occurs.
- In an
uncheckedcontext, the result is truncated by discarding any high-order bits that do not fit in the destination type.
For non-constant expressions (expressions that are evaluated at run-time) that are not enclosed by any
uncheckedoperators or statements, the default overflow checking context is
uncheckedunless external factors (such as compiler switches and execution environment configuration) call for checked evaluation.
For constant expressions (expressions that can be fully evaluated at compile-time), the default overflow checking context is always
checked. Unless a constant expression is explicitly placed in an
uncheckedcontext, overflows that occur during the compile-time evaluation of the expression always cause compile-time errors.