请高手帮帮忙，翻译以下指标

以下是全部代码：
请高手帮帮忙，主要是主函数部分弄不明白。
#property indicator_chart_window
#property indicator_buffers 2
#property indicator_color1 Red
#property indicator_color2 Blue
//----
extern int ATR = 20;
extern int Coeficient = 2;
//----
double Up[], Dn[];
string MODE;
bool first;
//+------------------------------------------------------------------+
//| Custom indicator initialization function |
//+------------------------------------------------------------------+
int init()
{
SetIndexBuffer(0, Up);
SetIndexStyle (0, DRAW_LINE, 0, 2);
SetIndexEmptyValue(0, 0.0);
SetIndexLabel (0, "Up");
//----
SetIndexBuffer(1, Dn);
SetIndexStyle (1, DRAW_LINE, 0, 2);
SetIndexEmptyValue(1, 0.0);
SetIndexLabel (1, "Dn");
//----
first=true;
//----
return(0);
}
//+------------------------------------------------------------------+
//| Custom indicator deinitialization function |
//+------------------------------------------------------------------+
int deinit()
{
first = true;
return(0);
}
//+------------------------------------------------------------------+
//| Custom indicator iteration function |
//+------------------------------------------------------------------+
//+------------------------------------------------------------------+
//| Custom indicator iteration function |
//+------------------------------------------------------------------+
int start()
{
int i, limit;
double REZ, md;
limit = Bars - ATR - 1;
//----
if(first)
{
md = 0;
for(i = 0; i < limit; i++)
md += iATR(NULL, 0, ATR, i);
REZ = Coeficient*iATR(NULL, 0, ATR, limit);
if(iATR(NULL, 0, ATR, limit) < md / limit)
{
Up[limit+1] = Low[limit+1] - REZ;
MODE = "UP";
}
if(iATR(NULL, 0, ATR, limit) > md / limit)
{
Dn[limit+1] = High[limit+1] + REZ;
MODE = "DN";
}
first = false;
}
//----
for(i = limit - 1; i >= 0; i--)
{
Dn = 0;
Up = 0;
REZ = Coeficient*iATR(NULL, 0, ATR, i);
//----
if(MODE == "DN" && Low[i+1] > Dn[i+1])
{
Up[i+1] = Low[i+1] - REZ;
MODE = "UP";
}
//----
if(MODE == "UP" && High[i+1] < Up[i+1])
{
Dn[i+1] = High[i+1] + REZ;
MODE = "DN";
}
//----
if(MODE=="UP")
{
if(Low[i+1] > Up[i+1] + REZ)
{
Up = Low[i+1] - REZ;
Dn = 0;
}
else
{
Up = Up[i+1];
Dn = 0;
}
}
//----
if(MODE=="DN")
{
if(High[i+1] < Dn[i+1] - REZ)
{
Dn = High[i+1] + REZ;
Up = 0;
}
else
{
Dn = Dn[i+1];
Up = 0;
}
}
}
return(0);
}

 

根据ｍｔ４的缓冲区长度决定REZ的初始值。
大概是用iATR()的平均值（从计算时间点到缓冲区的开始点）与REZ的差值正负，决定MODE是Up，或者是Down。
最后的显示，用计算时间点的(最低价 - REZ)、或者(最高价 + REZ)，设置显示的画线值。