What is MQL programming?

 To create a pending order in MetaTrader 4 (MT4) using MQL4, you need to write a script or an expert advisor (EA). Below is an example of an MQL4 code snippet to place a pending buy order (buy limit) in MT4.

//+------------------------------------------------------------------+
//|                        BuyLimitOrder.mq4                         |
//|         Generated by https://forexoptionst.blogspot.com          |
//+------------------------------------------------------------------+
#property strict

// Define input parameters for the pending order
input double LotSize = 1.0;         // Lot size
input double Price = 1.2000;        // Price for the pending order
input double StopLoss = 1.1950;     // Stop loss level
input double TakeProfit = 1.2100;   // Take profit level
input int Slippage = 3;             // Slippage in pips

//+------------------------------------------------------------------+
//| Expert initialization function                                   |
//+------------------------------------------------------------------+
int OnInit()
  {
   // Check if there are enough funds to place the order
   if(AccountFreeMarginCheck(Symbol(), OP_BUYLIMIT, LotSize) < 0)
     {
      Print("Not enough margin to place the order");
      return(INIT_FAILED);
     }

   // Place a Buy Limit order
   int ticket = OrderSend(Symbol(), OP_BUYLIMIT, LotSize, Price, Slippage, StopLoss, TakeProfit, "Buy Limit Order", 0, 0, clrGreen);
   
   if(ticket < 0)
     {
      Print("Error placing order: ", GetLastError());
      return(INIT_FAILED);
     }
   else
     {
      Print("Buy Limit order placed successfully. Ticket number: ", ticket);
      return(INIT_SUCCEEDED);
     }
  }
//+------------------------------------------------------------------+
//| Expert deinitialization function                                 |
//+------------------------------------------------------------------+
void OnDeinit(const int reason)
  {
  }
//+------------------------------------------------------------------+
//| Expert tick function                                             |
//+------------------------------------------------------------------+
void OnTick()
  {
  }
//+------------------------------------------------------------------+

Explanation:

1. Inputs:

   • LotSize: The size of the lot to trade.
   • Price: The price at which the pending buy limit order will be placed.
   • StopLoss: The price at which the stop loss will be set.
   • TakeProfit: The price at which the take profit will be set.
   • Slippage: The maximum slippage allowed in pips.

2. OnInit() Function:

   • This function initializes the expert advisor. It checks if there are enough funds to place the order using AccountFreeMarginCheck.
   • If there are enough funds, it places a buy limit order using OrderSend.
   • If the order is placed successfully, it prints the ticket number; otherwise, it prints an error message.

3. OnDeinit() Function:

   • This function is called when the expert advisor is removed. It is left empty in this example.

4. OnTick() Function:

   • This function is called on every tick. It is also left empty in this example.

How to use:

1. Open the MetaEditor from MetaTrader 4.
2. Create a new Expert Advisor and paste the code above into the editor.
3. Save and compile the code.
4. Attach the compiled EA to a chart in MetaTrader 4.

This script will place a buy limit order with the specified parameters when the EA is initialized. Modify the input parameters as needed before attaching the EA to the chart.