Hi newdigital,
Thank you very much for your
GREAT questions.
Quote:
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Originally Posted by newdigital
I have the questions.
1. You described about
#property indicator_buffer 1
Why do we need this buffer? What is it?
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1- you misspelled the code #property indicator_buffer
s 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.
Quote:
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Originally Posted by newdigital
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?
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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
Quote:
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Originally Posted by newdigital
3. Why
double ExtMapBuffer1[] ?
Is it always ExtMapBuffer and we need just remember it?
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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.
Quote:
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Originally Posted by newdigital
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 ????
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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;