Reference.Const History

Hide minor edits - Show changes to output

January 06, 2009, at 10:39 PM by Paul Badger -
Changed lines 5-6 from:
Constants defined with the ''const'' keyword obey the rules of ''[[scope | variable scoping]]'' that govern other variables. This, and the pitfalls of ''#define'', makes the ''const'' keyword a superior method for defining constants and is preferred over using ''[[define |#define]]''.
to:
Constants defined with the ''const'' keyword obey the rules of ''[[scope | variable scoping]]'' that govern other variables. This, and the pitfalls of using''#define'', makes the ''const'' keyword a superior method for defining constants and is preferred over using ''[[define |#define]]''.
January 06, 2009, at 10:38 PM by Paul Badger -
Deleted line 18:
Changed lines 21-23 from:
You can use either '''const''' or '''#define''' for creating numeric or string constants. For [[Array|arrays]], you will need to use '''const'''.

to:
You can use either '''const''' or '''#define''' for creating numeric or string constants. For [[Array|arrays]], you will need to use '''const'''. In general ''const'' is preferred over ''#define'' for defining constants.

January 06, 2009, at 10:37 PM by Paul Badger -
Changed lines 5-6 from:
Constants defined with the ''const'' keyword obey the rules of ''[[scope | variable scoping]]'' that govern other variables. This, and the pitfalls of ''[[define|#define]]'' makes the ''const'' keyword a superior method for defining constants and is preferred over using ''[[define |#define]]''.
to:
Constants defined with the ''const'' keyword obey the rules of ''[[scope | variable scoping]]'' that govern other variables. This, and the pitfalls of ''#define'', makes the ''const'' keyword a superior method for defining constants and is preferred over using ''[[define |#define]]''.
January 06, 2009, at 10:36 PM by Paul Badger -
Changed lines 5-6 from:
Constants defined with the ''const'' obey the rules of ''[[scope | variable scoping]]'' that govern other variables, however. This makes the ''const'' keyword a superior method for defining constants and is preferred over using ''[[define |#define]]''.
to:
Constants defined with the ''const'' keyword obey the rules of ''[[scope | variable scoping]]'' that govern other variables. This, and the pitfalls of ''[[define|#define]]'' makes the ''const'' keyword a superior method for defining constants and is preferred over using ''[[define |#define]]''.
January 06, 2009, at 10:35 PM by Paul Badger -
Changed lines 3-6 from:
The '''const''' keyword stands for constant. It is a variable ''qualifier'' that modifies the behavior of the variable.

'''const''' makes a variable "''read-only''". This means that the variable can be used just as any other variable of its type, but its value cannot be changed. You will get a compiler error if you try to assign a value to a '''const''' variable.
to:
The '''const''' keyword stands for constant. It is a variable ''qualifier'' that modifies the behavior of the variable, making a variable "''read-only''". This means that the variable can be used just as any other variable of its type, but its value cannot be changed. You will get a compiler error if you try to assign a value to a '''const''' variable.
January 06, 2009, at 10:30 PM by Paul Badger -
Changed lines 7-8 from:
Constants defined with ''const'' obey the rules of scoping that govern other variables, however. This makes the ''const'' keyword a superior method for defining constants and is preferred over using ''[[define |#define]]''.
to:
Constants defined with the ''const'' obey the rules of ''[[scope | variable scoping]]'' that govern other variables, however. This makes the ''const'' keyword a superior method for defining constants and is preferred over using ''[[define |#define]]''.
January 06, 2009, at 10:24 PM by Paul Badger -
Changed lines 5-6 from:
'''const''' makes a variable "''read-only''". This means that the variable can be used just as any other variable of its type, but its value cannot be changed. You will get a compiler error if you try to assign a value to a '''const''' variable.
to:
'''const''' makes a variable "''read-only''". This means that the variable can be used just as any other variable of its type, but its value cannot be changed. You will get a compiler error if you try to assign a value to a '''const''' variable.

Constants defined with ''const'' obey the rules of scoping that govern other variables, however. This makes the ''const'' keyword a superior method for defining constants and is preferred over using ''[[define |#define]]''.
July 17, 2007, at 08:24 PM by David A. Mellis -
Changed line 26 from:
*[[define]]
to:
*[[define | #define]]
July 17, 2007, at 06:09 PM by Paul Badger -
Changed lines 5-6 from:
'''const''' makes a variable "''read-only''". This means that the variable can be used just as any other variable of its type, but its value cannot be changed. You will get an error if you try to assign a value to a '''const''' variable.
to:
'''const''' makes a variable "''read-only''". This means that the variable can be used just as any other variable of its type, but its value cannot be changed. You will get a compiler error if you try to assign a value to a '''const''' variable.
May 31, 2007, at 04:36 PM by David A. Mellis -
Changed lines 3-6 from:
The '''const''' keyword stands for constant. Similar to the [[volatile]] keyword, it is called a variable ''qualifier'' and is used to modify the way the compiler and program treats the variable.

'''const''' is used to modify a variable by making it "''read-only''". This means that the variable can be used just as any other variable of its type, but the value cannot be changed. The compile.r will generate an error if you try to write to a '''const'''
to:
The '''const''' keyword stands for constant. It is a variable ''qualifier'' that modifies the behavior of the variable.

'''const''' makes a variable "''read-only''". This means that the variable can be used just as any other variable of its type, but its value cannot be changed. You will get an error if you try to assign a value to a '''const''' variable.
May 31, 2007, at 04:34 PM by David A. Mellis -
Changed lines 22-24 from:
It doesn't make much difference whether you use '''const''' or '''#define''' keywords for defining single number constants, for [[Array|arrays]] and [[String|strings]] though, you will need to use the '''const''' qualifier

to:
You can use either '''const''' or '''#define''' for creating numeric or string constants. For [[Array|arrays]], you will need to use '''const'''.

May 31, 2007, at 04:31 PM by David A. Mellis -
Changed lines 18-19 from:
@]]
to:
@]
May 29, 2007, at 10:12 PM by Paul Badger -
Changed lines 22-24 from:
It doesn't make much difference whether you use '''const''' or '''#define''' keywords for defining single number constants, for [[Array|arrays]] and [[strings]] though, you will need to use the '''const''' qualifier

to:
It doesn't make much difference whether you use '''const''' or '''#define''' keywords for defining single number constants, for [[Array|arrays]] and [[String|strings]] though, you will need to use the '''const''' qualifier

May 29, 2007, at 10:12 PM by Paul Badger -
Changed lines 22-24 from:
It doesn't make much difference whether you use '''const''' or '''#define''' keywords for defining single number constants, for [[Arrays|arrays]] and [[strings]] though, you will need to use the '''const''' qualifier

to:
It doesn't make much difference whether you use '''const''' or '''#define''' keywords for defining single number constants, for [[Array|arrays]] and [[strings]] though, you will need to use the '''const''' qualifier

May 29, 2007, at 10:12 PM by Paul Badger -
Changed lines 22-24 from:
It doesn't make much difference whether you use '''const''' or '''[[define|#define]]''' keywords for defining single number constants, for [[arrays|arrays]] and [[strings]] though, you will need to use the '''const''' qualifier

to:
It doesn't make much difference whether you use '''const''' or '''#define''' keywords for defining single number constants, for [[Arrays|arrays]] and [[strings]] though, you will need to use the '''const''' qualifier

May 29, 2007, at 10:10 PM by Paul Badger -
Changed lines 22-24 from:
It doesn't make much difference whether you use '''const''' or '''#define''' keywords for defining single number constants, for [[arrays|arrays]] and [[strings]] though, you will need to use the '''const''' qualifier

to:
It doesn't make much difference whether you use '''const''' or '''[[define|#define]]''' keywords for defining single number constants, for [[arrays|arrays]] and [[strings]] though, you will need to use the '''const''' qualifier

May 29, 2007, at 10:09 PM by Paul Badger -
Changed lines 22-24 from:
It doesn't make much difference whether you use '''const''' or '''#define''' keywords for defining single number constants, for [[arrays]] and [[strings]] though, you will need to use the '''const''' qualifier

to:
It doesn't make much difference whether you use '''const''' or '''#define''' keywords for defining single number constants, for [[arrays|arrays]] and [[strings]] though, you will need to use the '''const''' qualifier

May 29, 2007, at 10:08 PM by Paul Badger -
Changed lines 3-4 from:
The '''const''' keyword stands for constant. It can be used to modify a variable by making it "''read-only''". This means that the variable can be used just as any other variable of its type, but the value cannot be changed. The compile.r will generate an error if you try to write to a '''const'''
to:
The '''const''' keyword stands for constant. Similar to the [[volatile]] keyword, it is called a variable ''qualifier'' and is used to modify the way the compiler and program treats the variable.

'''const''' is used to modify a variable by making it "''read-only''". This means that the variable can be used just as any other variable of its type, but the value cannot be changed. The compile.r will generate an error if you try to write to a '''const'''
Changed lines 20-24 from:
to:
!!!! '''#define''' or '''const'''

It doesn't make much difference whether you use '''const''' or '''#define''' keywords for defining single number constants, for [[arrays]] and [[strings]] though, you will need to use the '''const''' qualifier

May 29, 2007, at 09:46 PM by Paul Badger -
Changed line 6 from:
to:
[@
Changed lines 14-21 from:
pi = 7; // illegal - you can't write to (modify) a constant
to:
pi = 7; // illegal - you can't write to (modify) a constant

@]]


See also:
*[[define]]
*[[volatile]]
May 29, 2007, at 09:45 PM by Paul Badger -
Added lines 1-14:
!! const keyword

The '''const''' keyword stands for constant. It can be used to modify a variable by making it "''read-only''". This means that the variable can be used just as any other variable of its type, but the value cannot be changed. The compile.r will generate an error if you try to write to a '''const'''

!!!! Example

const float pi = 3.14;
float x;

// ....

x = pi * 2; // it's fine to use const's in math

pi = 7; // illegal - you can't write to (modify) a constant

Share