string  ChartSymbol(
   long  chart_id=0      // 图表 ID
   );

//+------------------------------------------------------------------+
//| 脚本程序起始函数                                    |
//+------------------------------------------------------------------+
void OnStart()
  {
//--- 取得当前图表的交易品种并在日志中显示所取得的值
   string chart_symbol = ChartSymbol();
   Print("Current chart symbol: ", chart_symbol);

//--- 获取已有(本例中为当前)图表的ID
   long chart_id=ChartID();
   chart_symbol=ChartSymbol(chart_id);
   PrintFormat("Chart symbol with ID %I64d: %s", chart_id, chart_symbol);

//--- 当得到交易品种时设置随机图表ID
   chart_symbol = ChartSymbol(1234567890);
   if(chart_symbol=="")
      Print("The chart with ID 1234567890 does not exist");
   else
      Print("Chart symbol with ID 1234567890: ", chart_symbol);
   /*
   结果：
   Current chart symbol: GBPUSD
   Chart symbol with ID 132966427583395104: GBPUSD
   The chart with ID 1234567890 does not exist
   */
  }