Hi folks,

I’m so sorry for the two days delay in posting my new lesson.
Here (in my country) there was a holiday (3 days). And every time I open the computer to write the lesson I hear the door ring. New visitor every 3 hours

Anyway, this is the lesson , I hope you enjoy it.

Attached Images

lesson11.pdf (388.0 KB, 3991 views)

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Hope it helps !
Coders' Guru
Senior MQL programmer:
www.xpworx.com/custom.htm

I have the questions.

1. You described about
#property indicator_buffer 1
Why do we need this buffer? What is it?

2. We wrote:
double ExtMapBuffer1[]
And you described about arrays. As I understand we may use
int my_array [2] = {30, 70}
when
#property indicator_minimum 0
#property indicator_maximum 100 and we need to draw two horizontal lines (for example).
And if not 30 and 70. But 30.5 and 60.5 we will use double instead of int?

3. Why
double ExtMapBuffer1[] ?
Is it always ExtMapBuffer and we need just remember it?

4. int ExtCountedBars = 0
It means we are counting everything using curent zero bar. But in some cases we need to xalculate high or low for 300 bars for example.
Should we use
int ExtCountedBars = 300 ?
But if we need to change it from time to time we will use in property?
#property ????

Hi newdigital,

Thank you very much for your GREAT questions.

1- you misspelled the code #property indicator_buffers 1 (don't miss the s in buffer )
2- indicator_buffers is the number of memory allocated to draw your line(s). When you set the number (up to 8) you are telling MQL4: “Please allocate a memory buffer for me to draw my line”.
3- We need indicator_buffers when we need to draw lines.

You are right!

The data type of #property indicator_maximum & #property indicator_minimum is integer in the MQL4 guide. I forgot to mention that was wrong.
They actually are double. So, you can use something like that:
#property indicator_maximum 40.50
#property indicator_minimum 1.10

You can use any name you want. MQL4 wizard added this array and chose this name. It's good programming practice to leave it as it.


1- You can use any value you want instead of 0.
2- ExtCountedBars is a variable not a property.
3- If you want to enable the user to change this value use:
extern int ExtCountedBars = 0;

__________________
Hope it helps !
Coders' Guru
Senior MQL programmer:
www.xpworx.com/custom.htm

Hi folks,

Please download the updated version of the lesson.

__________________
Hope it helps !
Coders' Guru
Senior MQL programmer:
www.xpworx.com/custom.htm

The actually number of bars counted will be 301, correct?
Because 0 is counted as well.

<hr>
//---- indicators
SetIndexStyle(0,1, 5);
SetIndexBuffer(0,ExtMapBuffer1);
// Set the index number for the buffer.
string short_name = "My First Indicator is Running!";
IndicatorShortName (short_name);
// Indicator Short name places the name of the indicator in the upper left
// hand corner.
// This fuction has a return type of VOID. meaning it just does it's job and
// does not return any value to the calling function.

//34567891123456789212345678931234567894123456789512 3456789612345678971234567898 3456789912345678911234567892123456789312
// 80 and 132 Character ruler.

//----
return(1);
}

Question: why is return set to 1? Because the int Init () function returns a drawing object?

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Techguy
Never Lose A Password

Codersguru:

I added in this code and got this result:

if (counted_bars>0) counted_bars--;

int pos = Bars- counted_bars;
Print ("Bar index number is ", pos, ".");
// Bars is declared internally and equals the number of bars on the chart.

double dHigh , dLow, dResult; // a String of declarations.
Comment ("Hi, I'm here on the main Chart Window!");
// Prints a message in the top left corner of the chart.

The bar index number prints out as 2 , then 3, then 2,then 3??

Attached Images

barcountmystery.JPG (48.4 KB, 1533 views)

__________________
Kind Regards,

Techguy
Never Lose A Password

Codersguru asked this in Lesson 11:
"How will we work?
We will write the line(s) of the code we are going to explain then we will explain them
afterwards, if there are no topics, we will explain the line(s) of code directly. But at the
most of the time we will pause to discuss some general topics.
I want to here your suggestion about this method please!"

The line-by-line explanations are an excellent technique, and it was fine to have the pauses to discuss general topics.

Thanks to Codersguru for this helpful tutorial!

mcintyd1,

Thank you very much for your answer ! It's very helpful (& pleasant) comment.

I hope you enjoyed the lessons.

__________________
Hope it helps !
Coders' Guru
Senior MQL programmer:
www.xpworx.com/custom.htm

Hi
I had a run around trying to figure out where new indicators are stored. Finally I saw it was in the navigation window under 'custom indicators' - I did not see this mentioned in the lessons 10 through 13 - maybe I missed it.

Thanks for the great tutorials and I hope u managed to get u're car fixed.