Copy a string: Difference between revisions

This task is about copying a string. Where it is relevant, distinguish between copying the contents of a string versus making an additional reference to an existing string.

 

Ada provides three diffferent kinds of strings. The String type is a fixed length string. The Bounded_String type is a string with variable length up to a specified maximum size. The Unbounded_String type is a variable length string with no specified maximum size. The Bounded_String type behaves a lot like C strings, while the Unbounded_String type behaves a lot like the C++ String class.

 

Dest : Unbounded_String := Src;

 

'''Interpeter:''' [[QuickBasic]] 4.5, PB 7.1

 

dst[79] = 0;

 

 

Immutable strings - since they are immutable, you may get the same instance with its references count increased.

CString dst = src;

 

[[Category:C sharp]]

string src = "Hello";

string dst = src;

 

 

char[] src = "string";

char[] dest = src.dup;

 

 

Src = "Hello".

Dst = Src.

 

 

Forth strings are generally stored in memory as prefix counted string, where the first byte contains the string length. However, on the stack they are most often represented as <addr cnt> pairs. Thus the way you copy a string depends on where the source string comes from:

//"strCopy.equals(src)" is true

 

var src = "Hello";

var dst = src;

 

(setf orig "Hello")

(setf copied (copy-seq orig))

(eq orig copied)

nil

'''Interpeter:''' [[Perl]]

 

my $dst = $src;

 

 

$src = "Hello";

$dst = $src;

 

 

In Pop11 normal data are represented by references, so plain assignment

vars dst=copy(src);

'''Interpeter:''' Python 2.3, 2.4, 2.5

 

Be careful with 'is' - use it only when you want to compare the identity of the object. To compare string values, use '=='.

 

 

Copy a string by reference:

a copy as b

 

 

src="Hello"

dst=src.dup

 

 

var string: dest is "";

dest := "Hello";

 

 

set src "Rosetta Code"

set dst $src

 

" hello" is-data a

a string.clone is-data b

 

 

'''Platform:''' [[.NET]]