How does "IOS" infer the character encoding format of a text file

Overall idea:

Traverse the entire character encoding. The correct way to read the output conversion is the text file encoding format.

The code is as follows:

main.m//detect text character encoding format tips////Created by Chieh XI (duzixi) on 14-6-21.//Copyright (c) 2014 lanou3g.com All rights rese                rved.//#import <foundation/foundation.h>int Main (int argc, const char * argv[]) {@autoreleasepool {                                 Nsarray *arrencoding = @[@ (nsasciistringencoding), @ (nsnextstepstringencoding),                                 @ (nsjapaneseeucstringencoding), @ (nsutf8stringencoding),                                 @ (nsisolatin1stringencoding), @ (nssymbolstringencoding),                                 @ (nsnonlossyasciistringencoding), @ (nsshiftjisstringencoding),                                 @ (nsisolatin2stringencoding), @ (nsunicodestringencoding), @ (nswindowscp1251stringencoding), @ (Nswindowscp1252stringencodi                    NG),             @ (nswindowscp1253stringencoding), @ (nswindowscp1254stringencoding),                                 @ (nswindowscp1250stringencoding), @ (nsiso2022jpstringencoding),                                 @ (nsmacosromanstringencoding), @ (nsutf16stringencoding), @ (nsutf16bigendianstringencoding), @ (nsutf16littleendianstring Encoding), @ (nsutf32stringencoding), @ (nsutf32bigendianstr                ingencoding), @ (nsutf32littleendianstringencoding)]; Nsarray *arrencodingname = @[@ "nsasciistringencoding", @ "Nsnextstepstringe Ncoding ", @" nsjapaneseeucstringencoding ", @" NSUTF8         Stringencoding ",                            @ "nsisolatin1stringencoding", @ "nssymbolstringencoding", @ "nsnonlossyasciistringencoding", @ "Nsshiftjisstrin Gencoding ", @" nsisolatin2stringencoding ", @" Nsunic                                     Odestringencoding ", @" nswindowscp1251stringencoding ",                                     @ "nswindowscp1252stringencoding", @ "nswindowscp1253stringencoding", @ "nswindowscp1254stringencoding", @ "Nswindowscp1250stringencodin G ", @" nsiso2022jpstringencoding ", @" Nsmacosromanst Ringencoding ", @" nsutf16stringencoding ", @" NSUTF16 Bigendianstringencoding ", @ "nsutf16littleendianstringencoding", @ "nsutf32s                                     Tringencoding ", @" nsutf32bigendianstringencoding ",                @ "Nsutf32littleendianstringencoding"]; for (int i = 0; i < [arrencoding count]; i++) {unsigned long encodingcode = [Arrencoding[i] Unsignedlongva            Lue];            NSLog (@ "(%@)", Arrencodingname[i]);            Nserror *error = nil; NSString *filepath = @ "/users/dlios1/desktop/event.xml"; <---Here is the file path to view nsstring *astring = [nsstring stringwithcontentsoffile:filepath encoding:encodingcode ER            ror:&error];            NSLog (@ "error:%@", [Error localizeddescription]);            NSData *data = [astring Datausingencoding:encodingcode];            NSString *string = [[NSString alloc] Initwithdata:data Encoding:encodingcode]; NSLog (@ "%@", String); /*//if necessary, you can also create a file and then test [string writetofile:[nsstring stringwithformat:@]/users/dlios1/desktop/%@.                          XML ", Arrencodingname[i]] Atomically:yes Encoding:encodingcode             error:&error]; */}} return 0;}

How does "IOS" infer the character encoding format of a text file