Difference between revisions of "Data type"
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A '''data type''' is a classification of a variable or constant. There are certain data types that are predefined by any Pascal compiler (because you need them to make everything else). These are: | A '''data type''' is a classification of a variable or constant. There are certain data types that are predefined by any Pascal compiler (because you need them to make everything else). These are: | ||
− | * [[Byte|byte]] - an unsigned number in the range 0 to 255 | + | * [[Byte|byte]] - an unsigned number in the range 0 to 255. |
− | * [[Char|char]] - Single character | + | * [[Char|char]] - Single character. |
− | * [[Integer|integer]] - a whole number. | + | * [[Integer|integer]] - a whole number. FPC currently uses 4 bytes for integers. |
− | * [[Real|real]] - a number which may have a decimal point and possibly an exponent | + | * [[Real|real]] - a number which may have a decimal point and possibly an exponent. |
− | * [[Cardinal|cardinal]] - an unsigned whole number,ie it must be | + | * [[Cardinal|cardinal]] - an unsigned whole number,ie it must be positive. |
− | * [[Set|set]] - a collection of related elements; size depends on number of elements | + | * [[Set|set]] - a collection of related elements; size depends on number of elements. |
− | * [[Pointer|pointer]] - a reference to a location in memory, generally used for dynamic variables | + | * [[Pointer|pointer]] - a reference to a location in memory, generally used for dynamic variables. |
− | * [[Record|record]] - a combination of the above data types collected together | + | * [[Record|record]] - a combination of the above data types collected together. |
* [[Class|class]] | * [[Class|class]] | ||
− | * [[Object|object]] - a hybrid entity that may contain data and procedures to manipulate that data | + | * [[Object|object]] - a hybrid entity that may contain data and procedures to manipulate that data. |
Other data types are generally made with some combination of the above. FPC adds additional data types. | Other data types are generally made with some combination of the above. FPC adds additional data types. |
Revision as of 19:45, 25 January 2016
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A data type is a classification of a variable or constant. There are certain data types that are predefined by any Pascal compiler (because you need them to make everything else). These are:
- byte - an unsigned number in the range 0 to 255.
- char - Single character.
- integer - a whole number. FPC currently uses 4 bytes for integers.
- real - a number which may have a decimal point and possibly an exponent.
- cardinal - an unsigned whole number,ie it must be positive.
- set - a collection of related elements; size depends on number of elements.
- pointer - a reference to a location in memory, generally used for dynamic variables.
- record - a combination of the above data types collected together.
- class
- object - a hybrid entity that may contain data and procedures to manipulate that data.
Other data types are generally made with some combination of the above. FPC adds additional data types.