Peter Ammon <pe*********@ro cketmail.com> wrote in message news:<cj******* ***@news.apple. com>...
When I add an unsigned long long and an int, what type do each of the
values get promoted to before the addition is performed? What is the
type of the resulting expression? What occurs if the addition overflows
or underflows?
Try it on your machine/compiler and let us know.
On of these days I am going to figure out what the following means.
6.3.1.8 Usual arithmetic conversions
1 Many operators that expect operands of arithmetic type cause
conversions and yield result types in a similar way. The purpose
is to determine a common real type for the operands and result.
For the specified operands, each operand is converted, without
change of type domain, to a type whose corresponding real type
is the common real type. Unless explicitly stated otherwise, the
common real type is also the corresponding real type of the result,
whose type domain is the type domain of the operands if they are
the same, and complex otherwise. This pattern is called the usual
arithmetic conversions:
First, if the corresponding real type of either operand is long
double, the other operand is converted, without change of type
domain, to a type whose corresponding real type is long double.
Otherwise, if the corresponding real type of either operand is
double, the other operand is converted, without change of type
domain, to a type whose corresponding real type is double.
Otherwise, if the corresponding real type of either operand is
float, the other operand is converted, without change of type
domain, to a type whose corresponding real type is float.
Otherwise, the integer promotions are performed on both operands.
Then the following rules are applied to the promoted operands:
If both operands have the same type, then no further
conversion is needed.
Otherwise, if both operands have signed integer types or
both have unsigned integer types, the operand with the type
of lesser integer conversion rank is converted to the type
of the operand with greater rank.
Otherwise, if the operand that has unsigned integer type has
rank greater or equal to the rank of the type of the other
operand, then the operand with signed integer type is
converted to the type of the operand with unsigned integer
type.
Otherwise, if the type of the operand with signed integer
type can represent all of the values of the type of the
operand with unsigned integer type, then the operand with
unsigned integer type is converted to the type of the
operand with signed integer type.
Otherwise, both operands are converted to the unsigned
integer type corresponding to the type of the operand
with signed integer type.
