int nTop = lua_gettop(L);        // 栈内初始数,假设当前为0

    lua_newtable(L);                // push table

    lua_pushstring(L,"Line");        // push key "Line"
    lua_pushcfunction(L, Line);        // push value (function)Line;    // int Line(lua_State* pLua)
        // 当前栈值对应类型: table(-3),string(-2),function(-1)
    lua_settable(L,-3);                // table["Line"] = Line, pop key(-2) & value(-1)
        // 当前栈值对应类型: table(-1)

    lua_pushstring(L, "Circle");    // push key "Circle"
    lua_pushcfunction(L, Circle);    // push value (function)Circle;    // int Circle(lua_State* pLua)
    lua_settable(L, -3);            // table["Circle"] = Circle, pop key & value, pop key(-2) & value(-1)
        
    lua_setglobal(L,"Draw");        // 设置table(stack top)为全局变量，表名为Draw, 同时 pop stacktop
        // 当前栈为空

    lua_settop(L,nTop);                // 设置栈顶为初始数

    lua_dostring(L,"Draw.Line(100,50,34,34)");  //lua调用C/C++中的Line函数.   全局变量Draw(table)，key("Line")对应的函数(int Line(lua_State* pLua)),100,50,34,34,依次push入栈

// 查看lua栈内容
void stackDump(lua_State* L)
{
　　int top = lua_gettop(L);
　　for (int i = 1; i <= top; ++i)
    {
        int t = lua_type(L, i);
        switch (t)
        {
        case LUA_TSTRING:
            printf("'%s'", lua_tostring(L, i));break;
        case LUA_TBOOLEAN:
            printf(lua_toboolean(L, i) ? "true" : "false");break;
        case LUA_TNUMBER:
            printf("'%g'", lua_tonumber(L, i));break;
        default:
            printf("'%s'", lua_typename(L, t));break;
        }
        printf("    ");
    }
    printf("\n");

}