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Various rules in the C standard make unsigned char the basic type used for arrays suitable to store arbitrary non-bit-field objects: its lack of padding bits and trap representations, the definition of object representation, [7] and the possibility of aliasing. [12] The actual size and behavior of floating-point types also vary by implementation.
For Integers, the unsigned modifier defines the type to be unsigned. The default integer signedness outside bit-fields is signed, but can be set explicitly with signed modifier. By contrast, the C standard declares signed char, unsigned char, and char, to be three distinct types, but specifies that all three must have the same size and alignment.
The set of basic C data types is similar to Java's. Minimally, there are four types, char, int, float, and double, but the qualifiers short, long, signed, and unsigned mean that C contains numerous target-dependent integer and floating-point primitive types. [15]
The C programming language, for instance, supplies types such as Booleans, integers, floating-point numbers, etc., but the precise bit representations of these types are implementation-defined. The only C type with a precise machine representation is the char type that represents a byte. [9]
In C, native implementation-defined bit fields can be created using int, [a] unsigned int, signed int, _Bool (in C99), _BitInt(N), unsigned _BitInt(N) (in C23) or other implementation-defined types. In C++, they can be created using any integral or enumeration type; most C compilers also allow this.
For example, when shifting a 32 bit unsigned integer, a shift amount of 32 or higher would be undefined. Example: If the variable ch contains the bit pattern 11100101, then ch >> 1 will produce the result 01110010, and ch >> 2 will produce 00111001. Here blank spaces are generated simultaneously on the left when the bits are shifted to the right.
All C integer types have signed and unsigned variants. If signed or unsigned is not specified explicitly, in most circumstances, signed is assumed. However, for historic reasons, plain char is a type distinct from both signed char and unsigned char. It may be a signed type or an unsigned type, depending on the compiler and the character set (C ...
This type is not supported by compilers that require C code to be compliant with the previous C++ standard, C++03, because the long long type did not exist in C++03. For an ANSI/ISO compliant compiler, the minimum requirements for the specified ranges, that is, −(2 63 −1) [ 11 ] to 2 63 −1 for signed and 0 to 2 64 −1 for unsigned, [ 12 ...