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MQL5 简介（第 17 部分）：构建趋势反转 EA 交易·进阶篇

第 2/3 篇

本章目录

初始化与逐根 K 线抓取摆动低点
上升趋势线的摆动低点判定与绘制
摆动点变量与数据初始化的落地写法
用两个摆动低点拉出上升趋势线
下降趋势线的双顶确认与绘制
摆动高点判定的代码实现

◍ 初始化与逐根 K 线抓取摆动低点

EA 初始化收尾时把 low_price、high_price、time_price 三个数组用 ArraySetAsSeries(..., true) 设为时间序列，索引 0 对应最新一根 K 线；OnDeinit 里直接 ObjectsDeleteAll(chart_id) 清空图表对象，避免残留趋势线干扰下一轮加载。 OnTick 每次触发先用 CopyOpen / CopyClose / CopyLow / CopyHigh / CopyTime 把当前品种、指定周期、从偏移 1 开始的 bars_check 根数据搬进数组，跳过第 0 根未收盘 K 线，回测与实盘都不会把未完成棒算进摆动判定。允许画上升趋势线时，第一段 for 从 LookbackBars 扫到 bars_check - LookbackBars，调用 IsSwingLow 找最近的一个摆动低点，记下 first_low 与 first_low_time 后 break；第二段再扫同样区间，找时间更早且价格低于 first_low 的第二个摆动低点。两段都限定在 [LookbackBars, bars_check-LookbackBars] 内，意味着若 bars_check=100、LookbackBars=5，实际只在第 5~95 根之间找点，两端各留 5 根缓冲。外汇与贵金属杠杆高、滑点跳空频繁，这套扫低逻辑只在历史棒上跑，实盘新低若出现在第 0~4 根会被忽略，开 MT5 把 LookbackBars 调小到 2~3 可加快拐点捕获但假突破概率会上升。

MQL5 / C++

  ArraySetAsSeries(low_price, true);
  ArraySetAsSeries(high_price, true);
  ArraySetAsSeries(time_price, true);
  class="kw">return(INIT_SUCCEEDED);  class=class="str">"cmt">// Signal that the EA initialized successfully
  }
class=class="str">"cmt">//+------------------------------------------------------------------+
class=class="str">"cmt">//| Expert deinitialization function                                 |
class=class="str">"cmt">//+------------------------------------------------------------------+
class="type">void OnDeinit(const class="type">int reason)
  {
   ObjectsDeleteAll(chart_id);
  }
class=class="str">"cmt">//+------------------------------------------------------------------+
class=class="str">"cmt">//| Expert tick function                                             |
class=class="str">"cmt">//+------------------------------------------------------------------+
class="type">void OnTick()
  {
class=class="str">"cmt">// Copy the latest candlestick data into the arrays
   CopyOpen(_Symbol, time_frame, class="num">1, bars_check, open_price);       class=class="str">"cmt">// Open prices
   CopyClose(_Symbol, time_frame, class="num">1, bars_check, close_price);     class=class="str">"cmt">// Close prices
   CopyLow(_Symbol, time_frame, class="num">1, bars_check, low_price);         class=class="str">"cmt">// Low prices
   CopyHigh(_Symbol, time_frame, class="num">1, bars_check, high_price);       class=class="str">"cmt">// High prices
   CopyTime(_Symbol, time_frame, class="num">1, bars_check, time_price);       class=class="str">"cmt">// Candle times
class=class="str">"cmt">// If the user allows drawing of ascending trend line
   if(allow_uptrend)
     {
      class=class="str">"cmt">// First loop: Find the most recent swing low(first low)
      for(class="type">int i = LookbackBars; i < bars_check - LookbackBars; i++)
        {
         class=class="str">"cmt">// Check if current point is a swing low
         if(IsSwingLow(low_price, i, LookbackBars))
           {
            class=class="str">"cmt">// Store price and time of the first(latest) swing low
            first_low = low_price[i];
            first_low_time = time_price[i];
            break;  class=class="str">"cmt">// Exit loop after finding the first swing low
           }
        }
      class=class="str">"cmt">// Second loop: Find an earlier swing low that is lower than the first low
      for(class="type">int i = LookbackBars; i < bars_check - LookbackBars; i++)
        {
         class=class="str">"cmt">// Check for earlier swing low that is lower and occurs before the first low
         if(IsSwingLow(low_price, i, LookbackBars) && low_price[i] < first_low && time_price[i] < first_low_time)
           {
            class=class="str">"cmt">// Store price and time of the second(older) swing low
            second_low = low_price[i];
            second_low_time = time_price[i];
            break;  class=class="str">"cmt">// Exit loop after finding the second swing low
           }

上升趋势线的摆动低点判定与绘制

在 MT5 里自动画上升趋势线，核心是先确认两个摆动低点（swing low）且后一个低于前一个。原文用 IsSwingLow 函数以 lookback 为半径，检查目标 K 线左右各 lookback 根 lows 是否都更高，只有全满足才返回 true。绘制时先 ObjectCreate 连第二低点到第一低点，再用 OBJPROP_RAY_RIGHT 向右延伸。注意代码里先设 OBJPROP_TIMEFRAMES 为 OBJ_NO_PERIODS 暂时隐藏，等结构 valid（first_low > second_low && second_low > 0）才切到 OBJ_ALL_PERIODS 显示，并上色 clrBlue、线宽 3。输入参数给了具体默认：LookbackBars=5 控摆动识别灵敏度，bars_check=500 限定回溯根数，allow_uptrend 开关绘制。外汇与贵金属波动大，这类自动画线仅作结构参考，假突破概率不低，需结合实时价行为验证。下面这段是摆动低点判定与部分声明的原文，可直接拷进 MQ5 测：

MQL5 / C++

class="type">bool IsSwingLow(const class="type">class="kw">double &low[], class="type">int index, class="type">int lookback)
  {
   for(class="type">int i = class="num">1; i <= lookback; i++)
     {
      if(low[index] > low[index - i] || low[index] > low[index + i])
        class="kw">return false;
     }
   class="kw">return true;
  }
input ENUM_TIMEFRAMES time_frame = PERIOD_CURRENT;
input class="type">bool allow_uptrend = true;
input class="type">int LookbackBars = class="num">5;
input class="type">bool allow_downtrend = true;
class="type">int bars_check = class="num">500;
class="type">class="kw">double close_price[];
class="type">class="kw">double open_price[];
class="type">class="kw">double low_price[];
class="type">class="kw">double high_price[];
class="type">class="kw">datetime time_price[];
class="type">class="kw">double first_low;
class="type">class="kw">datetime first_low_time;
class="type">class="kw">double second_low;

「摆动点变量与数据初始化的落地写法」

要在 MT5 里自动画趋势线，第一步是把摆动高低点的容器和图表句柄先声明好。下面这段把第二低点时间、上升趋势线标签、图表 ID 分开存，逻辑上和后面要找的双低点对齐；高点的那组变量（first_high / second_high 等）则对称地留给下降趋势线用，标签写死成 "Down Trend" 方便后续 ObjectCreate 直接引用。 OnInit 里唯一要紧的事，是把 close/open/low/high/time 五个数组全部 ArraySetAsSeries(true)。不这么设，索引 0 会是历史最老 bar，你后面用 i=1 去 Copy 最新 N 根就全反了。 OnDeinit 只用 ObjectsDeleteAll(chart_id) 一句清掉本图表所有对象，避免 EA 重加载后旧趋势线堆在图上。OnTick 开头用 CopyOpen/CopyClose/CopyLow/CopyHigh/CopyTime 从偏移 1（跳过未收盘的当前 bar）拉取 bars_check 根数据——比如 bars_check 设 200，就是只处理已收盘的近 200 根，外汇与贵金属波动大，回看窗口过短容易把噪声当摆动点。 allow_uptrend 开关打开后，才进第一个 for 循环用 LookbackBars 做边界护垫找最近摆动低：i 从 LookbackBars 跑到 bars_check-LookbackBars，两端各留缓冲，避免数组越界也躲开图表最边缘的半根 K。

MQL5 / C++

class="type">class="kw">datetime second_low_time;   class=class="str">"cmt">// Time when the second swing low occurred
class="type">class="kw">string up_trend = "Up Trend";  class=class="str">"cmt">// Label used to name the ascending trend line object on the chart
class="type">long chart_id = ChartID();     class=class="str">"cmt">// Stores the current chart ID for referencing during object creation or manipulation

class="type">class="kw">double first_high;            class=class="str">"cmt">// Price value of the first identified swing high(latest high)
class="type">class="kw">datetime first_high_time;     class=class="str">"cmt">// Time when the first swing high occurred
class="type">class="kw">double second_high;           class=class="str">"cmt">// Price value of the second identified swing high(older high)
class="type">class="kw">datetime second_high_time;    class=class="str">"cmt">// Time when the second swing high occurred
class="type">class="kw">string down_trend = "Down Trend";  class=class="str">"cmt">// Label used to name the descending trend line object on the chart
class=class="str">"cmt">//+------------------------------------------------------------------+
class=class="str">"cmt">//| Expert initialization function                                     |
class=class="str">"cmt">//+------------------------------------------------------------------+
class="type">int OnInit()
  {
class=class="str">"cmt">// Set arrays as series so the newest bar is index class="num">0 ( start from the latest bar)
   ArraySetAsSeries(close_price, true);
   ArraySetAsSeries(open_price, true);
   ArraySetAsSeries(low_price, true);
   ArraySetAsSeries(high_price, true);
   ArraySetAsSeries(time_price, true);
   class="kw">return(INIT_SUCCEEDED);   class=class="str">"cmt">// Signal that the EA initialized successfully
  }
class=class="str">"cmt">//+------------------------------------------------------------------+
class=class="str">"cmt">//| Expert deinitialization function                                   |
class=class="str">"cmt">//+------------------------------------------------------------------+
class="type">void OnDeinit(const class="type">int reason)
  {
   ObjectsDeleteAll(chart_id);
  }
class=class="str">"cmt">//+------------------------------------------------------------------+
class=class="str">"cmt">//| Expert tick function                                               |
class=class="str">"cmt">//+------------------------------------------------------------------+
class="type">void OnTick()
  {
class=class="str">"cmt">// Copy the latest candlestick data into the arrays
   CopyOpen(_Symbol, time_frame, class="num">1, bars_check, open_price);      class=class="str">"cmt">// Open prices
   CopyClose(_Symbol, time_frame, class="num">1, bars_check, close_price);    class=class="str">"cmt">// Close prices
   CopyLow(_Symbol, time_frame, class="num">1, bars_check, low_price);        class=class="str">"cmt">// Low prices
   CopyHigh(_Symbol, time_frame, class="num">1, bars_check, high_price);      class=class="str">"cmt">// High prices
   CopyTime(_Symbol, time_frame, class="num">1, bars_check, time_price);      class=class="str">"cmt">// Candle times
class=class="str">"cmt">// If the user allows drawing of ascending trend line
   if(allow_uptrend)
     {
class=class="str">"cmt">// First loop: Find the most recent swing low(first low)
      for(class="type">int i = LookbackBars; i < bars_check - LookbackBars; i++)
        {

◍ 用两个摆动低点拉出上升趋势线

识别上升结构的核心，是先抓到最近的摆动低点，再往前找一个更低的摆动低点。下面这段逻辑用两次循环完成：第一次从近往远扫，命中 IsSwingLow 就记下 first_low 和 first_low_time 并 break；第二次从 LookbackBars 位置继续往后扫，找价格更低且时间更早的 second_low。

MQL5 / C++

class=class="str">"cmt">// Check if current point is a swing low
if(IsSwingLow(low_price, i, LookbackBars))
  {
   class=class="str">"cmt">// Store price and time of the first(latest) swing low
   first_low = low_price[i];
   first_low_time = time_price[i];
   break;   class=class="str">"cmt">// Exit loop after finding the first swing low
   }
  }
class=class="str">"cmt">// Second loop: Find an earlier swing low that is lower than the first low
for(class="type">int i = LookbackBars; i < bars_check - LookbackBars; i++)
  {
   class=class="str">"cmt">// Check for earlier swing low that is lower and occurs before the first low
   if(IsSwingLow(low_price, i, LookbackBars) && low_price[i] < first_low && time_price[i] < first_low_time)
     {
      class=class="str">"cmt">// Store price and time of the second(older) swing low
      second_low = low_price[i];
      second_low_time = time_price[i];
      break;   class=class="str">"cmt">// Exit loop after finding the second swing low
     }
  }
class=class="str">"cmt">// Create an ascending trend line from the second low to the first low
ObjectCreate(chart_id, up_trend, OBJ_TREND, class="num">0, second_low_time, second_low, first_low_time, first_low);
ObjectSetInteger(chart_id, up_trend, OBJPROP_TIMEFRAMES, OBJ_NO_PERIODS);   class=class="str">"cmt">// Temporarily hide line on all timeframes
class=class="str">"cmt">// If the swing structure is valid(i.e., second low is lower than first)
if(first_low > second_low && second_low > class="num">0)
  {
   class=class="str">"cmt">// Extend the trend line to the right
   ObjectSetInteger(chart_id, up_trend, OBJPROP_RAY_RIGHT, true);
   class=class="str">"cmt">// Show the trend line on all timeframes
   ObjectSetInteger(chart_id, up_trend, OBJPROP_TIMEFRAMES, OBJ_ALL_PERIODS);
   class=class="str">"cmt">// Set visual properties: class="type">color and thickness
   ObjectSetInteger(chart_id, up_trend, OBJPROP_COLOR, clrBlue);
   ObjectSetInteger(chart_id, up_trend, OBJPROP_WIDTH, class="num">3);
   }
  }
class=class="str">"cmt">//
class=class="str">"cmt">// Only proceed if drawing descending trend lines is enabled
 if(allow_downtrend)
  {
   class=class="str">"cmt">// First loop: Find the most recent swing high(first high)
   for(class="type">int i = LookbackBars; i < bars_check - LookbackBars; i++)
     {
      class=class="str">"cmt">// Check if the current bar is a swing high
      if(IsSwingHigh(high_price, i, LookbackBars))
        {
         class=class="str">"cmt">// Store the price and time of this latest swing high
         first_high = high_price[i];
         first_high_time = time_price[i];

逐行拆一下：IsSwingLow 用 LookbackBars 根 K 线作为左右对比窗口判定拐点；first_low 是离当前最近的那個低点，second_low 必须价格更低且时间在前，这才构成「更高的低点」雏形。ObjectCreate 以第二低点为起点、第一低点为终点画 OBJ_TREND，先设 OBJ_NO_PERIODS 隐藏，等 first_low > second_low 且 second_low>0 验证通过后，再开 RAY_RIGHT 向右延伸并切到 OBJ_ALL_PERIODS 全周期显示，线宽给到 3、蓝色。后半段 allow_downtrend 开关控制下降线绘制，同样先扫 first_high。外汇与贵金属杠杆高，这类自动趋势线仅描述已发生的摆动结构，后续价格跌破倾向失效，开 MT5 把 LookbackBars 从默认 5 调到 8，能明显过滤掉小周期噪音。

MQL5 / C++

class=class="str">"cmt">// Check if current point is a swing low
if(IsSwingLow(low_price, i, LookbackBars))
  {
   class=class="str">"cmt">// Store price and time of the first(latest) swing low
   first_low = low_price[i];
   first_low_time = time_price[i];
   break;   class=class="str">"cmt">// Exit loop after finding the first swing low
   }
  }
class=class="str">"cmt">// Second loop: Find an earlier swing low that is lower than the first low
for(class="type">int i = LookbackBars; i < bars_check - LookbackBars; i++)
  {
   class=class="str">"cmt">// Check for earlier swing low that is lower and occurs before the first low
   if(IsSwingLow(low_price, i, LookbackBars) && low_price[i] < first_low && time_price[i] < first_low_time)
     {
      class=class="str">"cmt">// Store price and time of the second(older) swing low
      second_low = low_price[i];
      second_low_time = time_price[i];
      break;   class=class="str">"cmt">// Exit loop after finding the second swing low
     }
  }
class=class="str">"cmt">// Create an ascending trend line from the second low to the first low
ObjectCreate(chart_id, up_trend, OBJ_TREND, class="num">0, second_low_time, second_low, first_low_time, first_low);
ObjectSetInteger(chart_id, up_trend, OBJPROP_TIMEFRAMES, OBJ_NO_PERIODS);   class=class="str">"cmt">// Temporarily hide line on all timeframes
class=class="str">"cmt">// If the swing structure is valid(i.e., second low is lower than first)
if(first_low > second_low && second_low > class="num">0)
  {
   class=class="str">"cmt">// Extend the trend line to the right
   ObjectSetInteger(chart_id, up_trend, OBJPROP_RAY_RIGHT, true);
   class=class="str">"cmt">// Show the trend line on all timeframes
   ObjectSetInteger(chart_id, up_trend, OBJPROP_TIMEFRAMES, OBJ_ALL_PERIODS);
   class=class="str">"cmt">// Set visual properties: class="type">color and thickness
   ObjectSetInteger(chart_id, up_trend, OBJPROP_COLOR, clrBlue);
   ObjectSetInteger(chart_id, up_trend, OBJPROP_WIDTH, class="num">3);
   }
  }
class=class="str">"cmt">//
class=class="str">"cmt">// Only proceed if drawing descending trend lines is enabled
 if(allow_downtrend)
  {
   class=class="str">"cmt">// First loop: Find the most recent swing high(first high)
   for(class="type">int i = LookbackBars; i < bars_check - LookbackBars; i++)
     {
      class=class="str">"cmt">// Check if the current bar is a swing high
      if(IsSwingHigh(high_price, i, LookbackBars))
        {
         class=class="str">"cmt">// Store the price and time of this latest swing high
         first_high = high_price[i];
         first_high_time = time_price[i];

下降趋势线的双顶确认与绘制

第二段循环从 LookbackBars 起向后扫，目标是找到比第一段循环里首个摆动高点更高、且时间更早的摆动高点。条件写成 IsSwingHigh(high_price, i, LookbackBars) && high_price[i] > first_high && time_price[i] < first_high_time，命中即存为 second_high 与 second_high_time 并 break，避免重复占用 CPU。拿到两个高点后，用 ObjectCreate 在图表上拉一条 OBJ_TREND：起点是更早期的 second_high_time / second_high，终点是 first_high_time / first_high。注意先设 OBJPROP_TIMEFRAMES 为 OBJ_NO_PERIODS 隐藏，防止在全部周期上画出半截线。结构校验靠 first_high < second_high && second_high > 0：旧高必须高于新高，才能算下降连线。通过后才把 OBJPROP_RAY_RIGHT 开为真向右延伸，时间帧切到 OBJ_ALL_PERIODS，颜色 clrDarkGreen、宽度 3 像素，肉眼更好认。低点判定交给 IsSwingLow：以 index 为中心向左右各扩 lookback 根 K，只要 low[index] 大于任一侧邻杆低点就返回 false，否则是摆动低点。把 lookback 设成 3 与设成 5，在 M15 黄金上筛出的摆动点数量可能差出 40% 以上，建议开 MT5 自己调参验证。外汇与贵金属波动剧烈，趋势线仅作概率参考，实盘仍属高风险。

MQL5 / C++

      break; class=class="str">"cmt">// Exit loop once the first swing high is found
       }
      }
      class=class="str">"cmt">// Second loop: Find an earlier swing high that is higher than the first high and occurred before it
      for(class="type">int i = LookbackBars; i < bars_check - LookbackBars; i++)
      {
       class=class="str">"cmt">// Check for earlier swing high that is higher and happened before the first one
       if(IsSwingHigh(high_price, i, LookbackBars) && high_price[i] > first_high && time_price[i] < first_high_time)
         {
          class=class="str">"cmt">// Store the price and time of this older swing high
          second_high = high_price[i];
          second_high_time = time_price[i];
          break;   class=class="str">"cmt">// Exit loop once the second swing high is found
         }
       }
      class=class="str">"cmt">// Create a trend line object from the second swing high to the first swing high
      ObjectCreate(chart_id, down_trend, OBJ_TREND, class="num">0, second_high_time, second_high, first_high_time, first_high);
      class=class="str">"cmt">// Initially hide the trend line across all timeframes to avoid partial drawing
      ObjectSetInteger(chart_id, down_trend, OBJPROP_TIMEFRAMES, OBJ_NO_PERIODS);
      class=class="str">"cmt">// Validate the swing structure:
      class=class="str">"cmt">// The older swing high should be higher than the later swing high to confirm a descending trend line
      if(first_high < second_high && second_high > class="num">0)
        {
         class=class="str">"cmt">// Extend the trend line indefinitely to the right for better visual guidance
         ObjectSetInteger(chart_id, down_trend, OBJPROP_RAY_RIGHT, true);
         class=class="str">"cmt">// Make the trend line visible on all chart timeframes
         ObjectSetInteger(chart_id, down_trend, OBJPROP_TIMEFRAMES, OBJ_ALL_PERIODS);
         class=class="str">"cmt">// Set the trend line class="type">color to dark green for clear distinction
         ObjectSetInteger(chart_id, down_trend, OBJPROP_COLOR, clrDarkGreen);
         class=class="str">"cmt">// Set the thickness of the trend line to class="num">3 pixels for better visibility
         ObjectSetInteger(chart_id, down_trend, OBJPROP_WIDTH, class="num">3);
        }
     }
}
class=class="str">"cmt">//+------------------------------------------------------------------+
class=class="str">"cmt">//| FUNCTION FOR LOWS                                                  |
class=class="str">"cmt">//+------------------------------------------------------------------+
class="type">bool IsSwingLow(const class="type">class="kw">double &low[], class="type">int index, class="type">int lookback)
  {
   for(class="type">int i = class="num">1; i <= lookback; i++)
     {
      if(low[index] > low[index - i] || low[index] > low[index + i])
        class="kw">return false;
     }
   class="kw">return true;
  }
class=class="str">"cmt">//+------------------------------------------------------------------+

「摆动高点判定的代码实现」

识别摆动高点（Swing High）是价格行为分析里过滤噪音的第一步。下面这段 MQL5 函数用左右对称回看的方式，判断某根 K 线高点是否真正胜出邻近区间。函数 IsSwingHigh 接收三个参数：high[] 为高点数组引用，index 为待判定 K 线位置，lookback 为向左右各回看的根数。例如 lookback=2 时，会对比 index 前后各 2 根共 4 根 K 线。核心逻辑是一个从 1 到 lookback 的循环：只要 index 位置的高点小于左侧任一根（index-i）或右侧任一根（index+i），立即返回 false；全部比对通过才返回 true。外汇与贵金属波动剧烈，lookback 设太小容易把毛刺当拐点，设太大则信号严重滞后，建议先在 EURUSD 的 M15 上用 3~5 做肉眼校验。

MQL5 / C++

class=class="str">"cmt">//| FUNCTION FOR HIGHS                                                                 |
class=class="str">"cmt">//+------------------------------------------------------------------+
class="type">bool IsSwingHigh(const class="type">class="kw">double &high[], class="type">int index, class="type">int lookback)
  {
   for(class="type">int i = class="num">1; i <= lookback; i++)
     {
      if(high[index] < high[index - i] || high[index] < high[index + i])
        class="kw">return false;
     }
   class="kw">return true;
  }