What are c plus plus programming character values?

Answer 1

Character values can be one of six data types: char, signed char, unsigned char, wchar_t, char16_t and char64_t.

The char type is the default character type for program text as used by the implementation's character set (usually some variant of ISO-646 such as ASCII) and is usually 8 bits in length. It is not safe to assume it is always 8-bits -- that is implementation defined -- but it will always be at least 8-bits. A char represents the smallest unit of storage on any architecture; every memory address is capable of storing exactly one char. Thus sizeof(char) is guaranteed to return a value of no less than 1. All other data types have lengths that are some multiple of sizeof(char). Very few architectures allow individual bits to be addressed, but you can use bitwise logic to determine the state of any individual bit in any value of any type up to the maximum word length available on the architecture (e.g., 64 bits on a 64-bit system). For data lengths larger than the largest word length (such as 128-bit), you need to split the data into smaller words (such as two 64-bit values).

A signed char is always at least as long as a char and is guaranteed signed. The valid range is at least -127 to 127 (not -128 to 127) since some systems use ones-complement notation (meaning -0 and +0 are treated as the same value, 0).

An unsigned char is always at least as long as a char and is guaranteed unsigned, with a valid range of at least 0 to 255.

A wchar_t is always at least as long as a char, but large enough to hold the largest character set supported by the implementation's locale, such as Unicode.

A char16_t is always at least 16-bits long, designed to cater for 16-bit character sets such as UTF-16.

A char32_t is always at least 32-bits long, designed to cater for 32-bit character sets such as UTF-32.

Your implementation may provide additional character types, however they are not guaranteed to be portable.

The data lengths and valid range for all built-in types can be determined by including the <limits> header. For example, to determine the minimum and maximum value of a char, use numeric_limits::<char>::min() and numeric_limits<char>::max(), respectively.