Writing an expert adviser in [ MQL4 ] - mql4

Question

So if I wanted an EA in MQL4 that took the open price and when current price was 10 pips below the open it places a buy order and when it was 10 pips above the open it sold. Only one order at a time and the open changed daily.
Q1: How could that run unstopped?
Q2: Would that even be profitable?
I know this is simple for some people to write but for me it's depressing.

Answer 1

A1: the simplest part ...
The MQL4 Expert Advisor type-of-code's execution can be principally run unstopped, supposing the execution engine, the MetaTrader Terminal 4, is being run in a nonstop mode. While there still remain the weekends available for service & maintenance tasks, the EA code, per se can be operated infinitely long, state-fully with an automated re-entrant safe re-launch self-protection ( OnInit(){...} + OnDeinit(){...} ).
#property copyright "Copyright © 1987-2016 [MS]"
#property link "nowhere.no"
#property version "0.00"
#property strict
extern int minDist2XTO = 10; // A minimum Distance To XTO
bool aGlobalMUTEX_LOCKED = False; // LOCK "only one order at a time"
//+------------------------------------------------------------------+
//| Expert initialization function |
//+------------------------------------------------------------------+
int OnInit()
{ // on-launch intialisation tasks go here:
return( INIT_SUCCEEDED );
}
//+------------------------------------------------------------------+
//| Expert deinitialization function |
//+------------------------------------------------------------------+
void OnDeinit( const int reason )
{ // pre-exit sanitisation tasks go here:
}
//+------------------------------------------------------------------+
//| Expert tick function |
//+------------------------------------------------------------------+
void OnTick()
{ // MAIN: this is being executed upon each anFxMarketEVENT's arrival
// GoLONG();
// GoSHORT();
}
//+------------------------------------------------------------------+
//| Tester function |
//+------------------------------------------------------------------+
double OnTester()
{ // back-testing utility calculation functions go here:
double retVal = 0.0;
return( retVal );
}
//+------------------------------------------------------------------+
void GoLONG()
{ // SELF-CONTROLLABLE ( might even get concurrently run in parallel to GoSHORT on dual resources )
// -------------------------------------------------------------------------------------------------------
static bool aNewBarEVENT = FALSE;
static int aLastBAR = EMPTY,
aCurrBAR = EMPTY;
static double GoLONG_LEVEL = EMPTY;
// -------------------------------------------------------------------------------------------------------
// TEST A STATE-SHIFT
RefreshRates();
aCurrBAR = iBars(_Symbol, PERIOD_D1 );
if ( aLastBAR != aCurrBAR )
{ aLastBAR = aCurrBAR; // .SET
aNewBarEVENT = TRUE; // .FLAG
// ----------------------- // .RESET in-BAR-registers
GoLONG_LEVEL = NormalizeDouble( iOpen( _Symbol, PERIOD_D1, 0 )
- minDist2XTO * _Point
);
// ----------------------
}
else
{ aNewBarEVENT = FALSE; // !FLAG
}
if ( !aGlobalMUTEX_LOCKED
&& Ask <= GoLONG_LEVEL
)
{
// XTO ... // .XTO
if ( success ) aGlobalMUTEX_LOCK = True;
}
}
//+------------------------------------------------------------------+
void GoSHORT()
{ // SELF-CONTROLLABLE ( might even get concurrently run in parallel to GoLONG on dual resources )
...
..
.
}
A2:
This question can be addressed quantitatively. Your trading idea can be tested and validated on the real-market data, so as to provide a reasonable amount of observations that either support or limit the expected performance expectations.
Without quantitative data from adequate TimeDOMAIN span of the market seasonality irregularities, the question cannot have a reasonably supported quantitative answer ( except for just an opinion ).
This goes far beyond a StackOverflow format of Q/A, but in principle back-testing ( with a support of an inbuilt mechanism of double OnTester(){...} post-processing facility ) and forward-testing ( with a support of demo-account forward runs ) are both being used in quant modelling, before any real trading strategy is ever exposed to execute any real market-risk.