C++ 裡頭寫一個 Function 但是透過 Lua 提供input引數並且回傳結果給Lua 輸出的辦法。

Lua 檔案

1 local ave, sum = average(22, 20, 45)
2 print("ave : ", ave, "sum = ", sum)

C++ 檔案

 1 int average(lua_State *L){
 2 
 3     int lua_args_count = lua_gettop(L);
 4 
 5     lua_Number sum = 0;
 6     for (int i = 0; i < lua_args_count; i++){
 
 7         sum += lua_tonumber(L, i);
 8     }
 9 
10     lua_pushnumber(L, sum / lua_args_count); // follow order to return value ave
11     lua_pushnumber(L, sum); // sum
12 
13     // return 2 number to Lua
14     return 2;
15 }
16 
17 int main(int argc, const char *argv[])
18 {
19     //cout << "lua test platform!!!" << endl;
 

20     string scriptnema = "main.lua";
21     string script_char = "print('123')";
22 
23     int luaError;
24     lua_State *L = luaL_newstate();
25     if (L == NULL)
26     {
27         cout << "luaL_newstate faile !!!" << endl;
28         return -1;
29     }
30     luaL_openlibs(L);
31
 
     lua_register(L, "average", average); // "average" --> Lua symbol call C++ function method (local ave, sum = average(11, 20, 63))
32 
33     luaError = luaL_dofile(L, scriptnema.c_str());
34     lua_close(L);
35     system("pause");
36     return 0;
37 }

第31行，這邊主要是讓Lua symbol 可以辨識 average的感覺，還有另一種辦法可以自己創造一個

自己的Lua環境(Lib)，打算在下一篇紀錄下來。

// "average" --> Lua symbol call C++ function method (local ave, sum = average(11, 20, 63))
lua_register(L, "average", average);