C++, Multilanguage/Localisation support

Question

what's the best way to add multilanguage support to a C++ program?

If possible, the language should be read in from a plain text file containing something like key-value pairs (§WelcomeMessage§ "Hello %s!").

I thought of something like adding a localizedString(key) function that returns the string of the loaded language file. Are there better or more efficient ways?

//half-pseudo code
//somewhere load the language key value pairs into langfile[]
string localizedString(key)
{
    //do something else here with the string like parsing placeholders
    return langfile[key];
}

cout << localizedString(§WelcomeMessage§);

Answer 1

Simplest way without external libraries:

// strings.h

enum
{
     LANG_EN_EN,
     LANG_EN_AU
};

enum
{
     STRING_HELLO,
     STRING_DO_SOMETHING,
     STRING_GOODBYE
};

// strings.c

char* en_gb[] = {"Well, Hello","Please do something","Goodbye"};
char* en_au[] = {"Morning, Cobber","do somin'","See Ya"};

char** languages[MAX_LANGUAGES] = {en_gb,en_au};

This will give you what you want. Obviously you could read the strings from a file. I.e.

// en_au.lang

STRING_HELLO,"Morning, CObber"
STRING_DO_SOMETHING,"do somin'"
STRING_GOODBYE,"See Ya"

But you would need a list of string names to match to the string titles. i.e.

// parse_strings.c

struct PARSE_STRINGS
{
    char* string_name;
    int   string_id;
}

PARSE_STRINGS[] = {{"STRING_HELLO",STRING_HELLO},
                   {"STRING_DO_SOMETHING",STRING_DO_SOMETHING},
                   {"STRING_GOODBYE",STRING_GOODBYE}};

The above should be slightly easier in C++ as you could use the enum classes toString() method (or what ever it as - can't be bothered to look it up).

All you then have to do is parse the language files.

I hope this helps.

PS: and to access the strings:

languages[current_language][STRING_HELLO]

PPS: apologies for the half c half C++ answer.