7 Standard conversions [conv]

7.8 Integral conversions [conv.integral]

1
#
A prvalue of an integer type can be converted to a prvalue of another integer type.
A prvalue of an unscoped enumeration type can be converted to a prvalue of an integer type.
2
#
If the destination type is unsigned, the resulting value is the least unsigned integer congruent to the source integer (modulo where n is the number of bits used to represent the unsigned type).
[ Note
:
In a two's complement representation, this conversion is conceptual and there is no change in the bit pattern (if there is no truncation).
— end note
 ]
3
#
If the destination type is signed, the value is unchanged if it can be represented in the destination type; otherwise, the value is implementation-defined.
4
#
If the destination type is bool, see [conv.bool].
If the source type is bool, the value false is converted to zero and the value true is converted to one.
5
#
The conversions allowed as integral promotions are excluded from the set of integral conversions.