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How to make a program in metatrader.

  • #21
  • Nov 28, 2008 5:03pm Nov 28, 2008 5:03pm
Now this 10 period ema is not very useful, so we need to have a way of changing the inputs for the periods and maybe the inputs for the type of MA like exponential or smoothed or simple or weighted.
  • #22
  • Edited 5:46pm Nov 28, 2008 5:06pm | Edited 5:46pm
//+------------------------------------------------------------------+
//| Indicator Template.mq4 |
//| |
//| |
//+------------------------------------------------------------------+
#property copyright ""
#property link ""
#property indicator_chart_window
#property indicator_buffers 1
extern MAPeriod = 10;
extern MAType = 0; // 0 = SMA 1 = EMA 2 = SMMa smoothed 3 = WMMA weighted
double Buffer1[];
//+------------------------------------------------------------------+
//| Custom indicator initialization function |
//+------------------------------------------------------------------+
int init()
{
//---- indicators
SetIndexBuffer(0, Buffer1);
SetIndexStyle(0, DRAW_LINE);
//----
return(0);
}
//+------------------------------------------------------------------+
//| Custom indicator deinitialization function |
//+------------------------------------------------------------------+
int deinit()
{
//----

//----
return(0);
}
//+------------------------------------------------------------------+
//| Custom indicator iteration function |
//+------------------------------------------------------------------+
int start()
{

int limit;
int counted_bars=IndicatorCounted();
//---- last counted bar will be recounted
if(counted_bars>0) counted_bars--;
limit=Bars-counted_bars;
for(int i=0; i<limit; i++)
{
Buffer1[i] = iMA(Symbol(),0, ,MAPeriod, 0, MAType, PRICE_CLOSE, i);

}
//----

//----
return(0);
}
//+------------------------------------------------------------------+

Note the external input variables in red that will show up in the input window when you load the indicator

Also note that // means a comment for you and will be ignored by the computer through the end of the line it is on.

Now you change the PRICE_CLOSE in this indicator to use a extern input variable like AppliedPrice to be able to change the price applied to the MA right now it is on the close.

Your choices are :

PRICE_CLOSE0Close price. 0
PRICE_OPEN1Open price 1
PRICE_HIGH2High price. 2
PRICE_LOW3Low price. 3
PRICE_MEDIAN4Median price, (high+low)/2. 4
PRICE_TYPICAL5Typical price, (high+low+close)/3. 5
PRICE_WEIGHTED6Weighted close price, (high+low+close+close)/4. 6
  • #23
  • Nov 28, 2008 5:12pm Nov 28, 2008 5:12pm
Post it here when you are finished.
  • #24
  • Nov 28, 2008 5:14pm Nov 28, 2008 5:14pm
Also note, that if you want more info on any function or command in MT4, place your curser on that word and then press F1 It will bring up the help in the box at the bottom of the MT4 editor

Example by placing the curser on iMA and pressing F1 I get this
Attached Image (click to enlarge)
Click to Enlarge Name: ScreenHunter_068.jpg Size: 64 KB
  • #25
  • Edited 5:29pm Nov 28, 2008 5:19pm | Edited 5:29pm
Also note, that it will not draw any line yet, because something is missing.

load this indicator into your editor and put the curser on the SetIndexStyle press F1 then tell me what you see that is missing.
  • #26
  • Nov 28, 2008 5:19pm Nov 28, 2008 5:19pm
Quoting smjones
Post it here when you are finished.
Okay I will do that. I'm not sure if I will make it today because it's late in the evening where I live and I have only slept 5-6 hours.

I just copied the code into metaeditor and there are some compilation errors.
If slaughterhouses had glass walls, everyone would be a vegetarian!
  • #27
  • Nov 28, 2008 5:23pm Nov 28, 2008 5:23pm
And there was something else missing. I did not tell the compiler how many arrays I am using. So if you refer back to the last copy of the indicator I posted, see the blue to see what was missing. If I had wanted to draw two lines, I would need two arrays and then the #property buffers would be 2 also.
  • #28
  • Nov 28, 2008 5:24pm Nov 28, 2008 5:24pm
Take your time. I will check back later.
  • #29
  • Nov 28, 2008 5:25pm Nov 28, 2008 5:25pm
Quoting smjones
Also note, that it will not draw any line yet, because something is missing.

load this indicator into your editor and put the curser on the SetIndexStyle then tell me what you see that is missing.
I see that you have not defined a color for the line.
If slaughterhouses had glass walls, everyone would be a vegetarian!
  • #30
  • Nov 28, 2008 5:27pm Nov 28, 2008 5:27pm
There is also a mistake in the iMA function I wrote, double click on the error and see if you can find it. Hint. I put in one too many of it.
  • #31
  • Nov 28, 2008 5:29pm Nov 28, 2008 5:29pm
See you later. Take your time.
  • #32
  • Nov 28, 2008 5:30pm Nov 28, 2008 5:30pm
Quoting Gambler180
I see that you have not defined a color for the line.
Bingo. Define a color.
There is also another way of defining a color, but I will talk about that later.
  • #33
  • Nov 28, 2008 5:38pm Nov 28, 2008 5:38pm
Also, I declaered an external for MAPeriod and for MAType, but I did not say what type of variable it should be. The proper format would be

extern int MAPeriod; and extern int MAType;

See it could have been a string or a double or bool depending on the type of data the extern variable was going to hold. In this case these are integers as noted by looking F1 for iMA parameters
  • #34
  • Nov 28, 2008 5:41pm Nov 28, 2008 5:41pm
Here it is correct and with everything right.

Please don't look until you try to see where the errors are. Then see if you got it right.

Don't forget to add the price type

Now I am done for a while... Go Sleep.
Attached File(s)
File Type: mq4 Gamblertest 1.mq4   2 KB | 259 downloads
  • #35
  • Edited 6:40pm Nov 28, 2008 6:23pm | Edited 6:40pm
Quoting smjones
Here it is correct and with everything right.
Please don't look until you try to see where the errors are. Then see if you got it right.
Don't forget to add the price type
Now I am done for a while... Go Sleep.
I think it's easiest to learn of I tell you what we do line by line and then you tell me when I am wrong.

#property indicator_chart_window
Here we choose to have the indicator on the price chart. We could also have chosen to write #property indicator_separate_window

#property indicator_buffers 1
The number of lines we need. If we need 2 moving averages or if we need a moving average and a RSI line then this number should be 2.

extern MAPeriod = 10;
Here we make an external variable called MAPeriod and the default value is 10

extern MAType = 0; // 0 = SMA 1 = EMA 2 = SMMa smoothed 3 = WMMA weighted
Here we creates an external variable which makes the user able to choose what kind of moving average it should be.

double Buffer1[];
Here we have declared an array that is called buffer1

int init()
Init is a function that should be called during the module initialization.

{
Why does the next part of the code start with braces when it is not a loop we have. As I have understood it we should only use braces when we have multiple statements inside a loop. For example

for(int i=1;i<=15;i++)
{
Print(i);
PlaySound("alert.wav");
}
If slaughterhouses had glass walls, everyone would be a vegetarian!
  • #36
  • Edited 7:29pm Nov 28, 2008 6:47pm | Edited 7:29pm
Quoting Gambler180
I think it's easiest to learn of I tell you what we do line by line and then you tell me when I am wrong.

#property indicator_chart_window
Here we choose to have the indicator on the price chart. We could also have chosen to write #property indicator_separate_window
Yes this is correct

#property indicator_buffers 1
The number of lines we need. If we need 2 moving averages or if we need a moving average and a RSI line then this number should be 2.
Yes this is correct
extern MAPeriod = 10;
Here...
int init()
Init is a function that should be called during the module initialization.

{
Why does the next part of the code start with braces when it is not a loop we have. As I have understood it we should only use braces when we have multiple statements inside a loop. For example

for(int i=1;i<=15;i++)
{
Print(i);
PlaySound("alert.wav");
}
You are correct except there are 2 statements in this for loop.
Note just look for ";" this ends a statement. See there are 2 of them

Please note that whenever you are using any function it will use the following format

int Myfunction ( incomming variables here)
{
your programming here.

return( varable to be returned);
}

So because init is a function, it must have the braces. You can declare a function to be a int or a double or a string or just a void. What this means is the type of data that will be sent back to the command that called it. If it is a void, no data is sent back. Note that Init() is a int type
  • #37
  • Nov 28, 2008 6:48pm Nov 28, 2008 6:48pm
My post was cut off. I will add the rest
  • #38
  • Edited 7:03pm Nov 28, 2008 6:51pm | Edited 7:03pm
Quote
double Buffer1[];
Here we have declared an array that is called buffer1
Yes. this will be used by the for loop in the start function
Note that this is a varable that can conatain a fraction of a number like 1.12345. An int would be an integer like 1 2 3 4 5 6000 a bool would be true or false a string would be "some text"

Quote
extern MAPeriod = 10;
Here we make an external variable called MAPeriod and the default value is 10
Yes, however I left out the int after the extern. as I stated above.

extern MAType = 0; // 0 = SMA 1 = EMA 2 = SMMa smoothed 3 = WMMA weighted
Here we creates an external variable which makes the user able to choose what kind of moving average it should be.
Yes however I left out the int after the extern like the MAPeriod.
..
  • #39
  • Nov 28, 2008 7:09pm Nov 28, 2008 7:09pm
Quote
for(int i=1;i<=15;i++)
{
Print(i);
PlaySound("alert.wav");
}
You are correct except there are 2 statements in this for loop.
Note just look for ";" this ends a statement. See there are 2 of them

Please note that whenever you are using any function it will use the following format

int Myfunction ( variables here)
{
your programming here.

return( varable to be returned);
}

So because init is a function, it must have the brackets. You can declare a function to be a int or a double or a string or just a void. What this means...

So every time I have a function I should use brackets, even if there only is one statement?
If slaughterhouses had glass walls, everyone would be a vegetarian!
  • #40
  • Nov 28, 2008 7:11pm Nov 28, 2008 7:11pm
Quoting Gambler180
So every time I have a function I should use brackets, even if there only is one statement?
Yes you must use brackets to define a function and the command word return; either as
return(some number); or if your function is void, just return;
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