Data Types — Integer Data Types
C and C++ have a number of basic data types. Each have specific uses and advantages, depending on the application.In general, the data types can be divided into two categories; Integer types and Floating Point types.
Integer types:
| Name | Size (in bits, on x86) | Range | Notes |
| bool | 8 (top 7 bits are ignored) | 0 or 1 | C++ only |
| char | 8 | -128 to 127(signed) or 0-255(unsigned) | standard issue "byte" |
| short | 16 | -32768 to 32767(signed) or 0-65536(unsigned) | just like a char, only twice as large |
| int | 32 | -2147483648 to 2147483647(signed) or 0-4294967296(unsigned) | standard-issue integer number type |
| long | 32 (can be 64 on other architectures) | same as int | ditto |
| long long | 64 (this is a non-standard GNU extension) | -9223372036854775808 to 9223372036854775807(signed) or 0-18446744073709551616(unsigned) | For very huge integers |
Floating Point types:
| Name | Size (in bits, on x86) | Range | Notes |
| float | 32 | +/- 1.4023x10-45 to 3.4028x10+38 | general purpose real-number |
| double | 64 | +/- 4.9406x10-324 to 1.7977x10308 | higher-precision real number |
| long double | 96 (this is a non-standard GNU extention) | ??? | For numbers with very large ranges and high precision |
Note that all Floating Point Types are always signed (they can be positive or negative), while Integer Types can be either signed or unsigned. Making an integer unsigned means that it is always non-negative and can count twice as high as a signed variable of the same type.
-- discuss ISO C99 sizes, as well as combinations (long char, long int, etc).