why no tick-actualization

Hello everyone,

this is my first message in this forum. Some months of trading. Some years of programming (pascal, basic and a little c).

But here, I try and try and ..... but can't find no solution. So I tried with a little example from "S. Kovalyov, Programming in Algorithmic Language ", but this doesn't work too.

Here is a little, modified code
-----------START-----------
//countiter.mq4
// The code should be used for educational purpose only.
//--------------------------------------------------------------------

int init()
{
//----
Alert ("Function init() triggered at start");// Alert

return; // Exit init()
//----
return(0);
}

int start() // Special funct. start()
{
int i, Count; // Declaring variables
for (i=1; i<=5; i++) // Show for 5 ticks
{
Count=0; // Clearing counter
while(RefreshRates()==false) // Until...
{ //..a new tick comes
Count = Count+1; // Iteration counter
}
Alert("Tick ",i,", loops ",Count); // After each tick
}
return; // Exit start()
}


The only message that appears on the alert-window:
"Function init() triggered at start"

and I expected something like

Tick 3 98622348
Tick 2 64534421
Tick 1 32343443

the chart is a simple EURUSD M1-chart with no other EA's or Indicators.
But it's a demo account.



Can anyone help me? This would be very kind of You

Problem is solved - Thank You and sorry,

so stupid, it was simply the fact that EA wasn't activated in MT. oh no

The code above does work as a script at least. It gets a bit too hard on the CPU though. It might be worth adding Sleep() call (if not an indicator) and IsStopped() check to the internal loop.

How do you run the example?

Hello Irtron,

thank You very much for Your reply. The problem is when I start from the end, that means with codeing and not from the beginning - handling MT.

I thought:" the Init runs, why not the rest", not knowing, that EA has to be activated and a exit comes with start ().

sorry

You should not do it like this. start() itself will be called for every tick, your script should be event driven, the event is the arrival of a new tick. you should process only this one tick in start() and immediately return.

The usage of long polling loops in these functions is possible, but you should only do if there is no other option and you cannot do this in indicators, only in expert advisors since indicators run in the GUI thread and you block the whole Metatrader GUI until start() returns.

If you need exactly 5 ticks you could set a global counter to 0, then in start() write the current price to an array, increase the counter, and only if the counter has reached 5 then do what must be done with the last 5 ticks and reset the counter, else just return.

You confusing EA and scripts here. start() function of the former is triggered by upcoming ticks indeed and RefreshRates() is necessary to make sure that the trade environment hasn't changed whilst start() is running. The latter (a script) runs its start() just once and it's suitable for asynchronous processing like in the code above. It's far from perfect though as I mentioned already and should be considered as an example for educational purposes only exactly as the copyright states.