On Fri, 16 Jan 2009 10:30:53 +0300, Qian Xu <quian...@stud.tu-ilmenau.de> wrote:
When shall I use some_var.dup and when not? Is there any guidlines? --Qiansua
.dup is typical way to makes a copy of variable: char[] greetings = "Hello, World!".dup; You usually do this when you want to modify variable that you are not allowed modify in-place. Consider the following example: auto greetings = "Hello, World!"; The "Hello, World!" string is not allowed to be modified, because it could be shared throughot the project and will be most probably put in a read-only memory causing segfault at modification. But it you need to have a modified version of this this, you create its copy (duplication, or 'dup' for short) and make whatever changes you want to it: char[] copy = greetings.dup; copy[0] = "T"; // copy -> "Tello, World!" .dup may be applied to arrays (including strings and maps aka associative arrays). You should write your own .dup method for your classes (deciding whether you want a deep copy or not), and it is not needed for struct, because assignment does everything for you (unless you want deep copy). Hope that helps.
