This article includes a list of references, but its sources remain unclear because it has C Language E Balagurusamy Pdf inline citations. C syntax makes use of the maximal munch principle. The C language represents numbers in three forms: integral, real and complex. This distinction reflects similar distinctions in the instruction set architecture of most central processing units.
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. C’s integer types come in different fixed sizes, capable of representing various ranges of numbers.
Although char can represent any of C’s “basic” characters, a wider type may be required for international character sets. The representation of some types may include unused “padding” bits, which occupy storage but are not included in the width. The char type is distinct from both signed char and unsigned char, but is guaranteed to have the same representation as one of them. The _Bool and long long types are standardized since 1999, and may not be supported by older C compilers.
In general, the widths and representation scheme implemented for any given platform are chosen based on the machine architecture, with some consideration given to the ease of importing source code developed for other platforms. In addition to the standard integer types, there may be other “extended” integer types, which can be used for typedefs in standard headers. For more precise specification of width, programmers can and should use typedefs from the standard header stdint. Integer constants may be specified in source code in several ways. Each of the enumerated constants has type int.
Some compilers warn if an object with enumerated type is assigned a value that is not one of its constants. However, such an object can be assigned any values in the range of their compatible type, and enum constants can be used anywhere an integer is expected. Subsequent references to a specific enumerated type use the enum keyword and the name of the enum. The floating-point form is used to represent numbers with a fractional component. Floating-point constants may be written in decimal notation, e.
Decimal scientific notation may be used by adding e or E followed by a decimal exponent, also known as E notation, e. It also defines other limits that are relevant to the processing of floating-point numbers. Every object has a storage class. Objects with automatic storage are local to the block in which they were declared and are discarded when the block is exited.
The extern storage class specifier indicates that the storage for an object has been defined elsewhere. When used inside a block, it indicates that the storage has been defined by a declaration outside of that block. When used outside of all blocks, it indicates that the storage has been defined outside of the compilation unit. The extern storage class specifier is redundant when used on a function declaration. Types can be qualified to indicate special properties of their data.