Dictionary with two (or more) languages and change it when code is running - c++

Question

I have to display some sentences on a screen.
However, the language can change if the user want to, so I do not want but I can do that :
if(language==1)
{
printf("Hello sir");
}
else if(language==2)
{
printf("Hola senor");
}
OR
printf("%s",language == 1 ? "Hello sir" : "Hola senor");
I do not want that because I have a lot of iterations.
Can I use map or enum and change it during code is running, I was thinking about a things like that :
#define MESSAGE_HELLO "Hello sir" OR "Hola senor"
printf("%s",MESSAGE_HELLO);
Do you have an idea ? Can you help me please ?

Answer 1

You can use some internationalization library that might help you. But here I will focus on how one can solve such a problem. Naturally, you need to have a set of languages, a set of message keys and a relationship between message keys and the languages, which would hold the actual message. Let's see some solutions:
Language file
You can store english.txt, etc. which would look like this:
hello_world="Hello World"
goodbye="Good bye"
and some other language, hungarian.txt for example:
hello_world="Heló Világ"
goodbye="Viszontlátásra"
etc.
Now, you can create an array of Map<String, Map<String, String>>, loop the languages, for each language process the corresponding file and fill the map accordingly.
Database
You can store a languages table, a message_keys table and a messages table. The messages table would have a foreign key pointing to languages and another one to message_keys and the actual message would be stored there as well. You could have an API that you could use in order to request items or groups of messages in a certain language.
There are many possible solutions.

Answer 2

In the professional world, I have often used tables (arrays) of phrases. Each slot in the array represents the phrase in another language.
static const char str_hello[] =
{
/* English */ "hello",
/* Spanish */ "hola",
/* German */ "guten tag",
//...
};
This has worked well in embedded systems.

Answer 3

You probably can create two maps for the sentences you want to translate - one map for one language - and then create a pointer to one of the maps. Then use pointer and [] to take sentences you need. Also, the pointer can be changed so that it points to another map at any moment.

Answer 4

Finally, I found a solution that fits with my requirements.
I use a .json file with all sentences and the languages I use.
{
"my-encoding": "UTF-8",
"messages": [
{
"MESS_HELLO": {
"english": "Hello",
"spanish": "Hola"
}
},
{
"MESS_GOODBYE": {
"english": "Bye",
"spanish": "Adios"
}
},
.......
]
}
To use .json file in C++, I included json-c lib in my project.
After loading the json file, I put it in a
std::unordered_map<std::string, std::unordered_map<std::string, std::string>> m_myTable;
With an ID declared in cpp (same as MESS_HELLO or MESS_GOODBYE).
It looks like that :
//"MESS_HELLO" -> { "english" -> "Hello" ; "spanish" -> "Hola" }
//"MESS_GOODBYE" -> { "english" -> "Bye" ; "other_language" -> "mess_in_other_language" ; +++ }
With that type I can do :
Easily add a new message by changing .json file + declaring in code a new ID
Modify the text by only change .json file
Add a new language by adding to .json file + adding several lines in code, but not a big deal.
To display it, I do something like
const auto &text_it = m_myTable.find("MESS_HELLO")
const auto &language_it = text_it->second.find("english");
printf("%s",language_it->second); //print Hello
Of course, it's in functions and well implemented, but I can't tell more about that.