Attachments: Coding Tutorial

Coding Tutorial

#1
First Post: Edited Dec 2, 2009 12:21am Dec 1, 2009 8:53pm | Edited Dec 2, 2009 12:21am

tomhliles
| Additional Username | Joined Dec 2006 | 163 Posts

i am going to attempt to create a tutorial, that anyone can understand, without any prior knowledge of coding

i recommend that you do each code your self, rather than copy n paste

i have a 8th grade education
i have no prior coding knowledge
i am in construction by trade

i started learning forex about 6 years ago
about 4-5 years ago i started teaching my self to code

90%+ of all my knowledge came from the editors help menu, trial n error

i only wish there was good tutorials when i started

you can do it

#2
Dec 1, 2009 9:08pm Dec 1, 2009 9:08pm

tomhliles
| Additional Username | Joined Dec 2006 | 163 Posts

first thing to know, is how {these brackets work}

lets imaging our program is a building, the building has many floors

we must be back on the ground floor to get out

heres the basic structure of a function

a function does something, or returns some value

a ea comes default with 3 functions

init()
deinit()
start()

heres what the start() function looks like in a new ea

int start()
{
//----
// were on the first floor
//----
return(0);
}

now lets look at this is another way

int start(){return(0);}

we can make this look any way we want, the result is no different

int start(){
return(0);
}

this is the basic structure of a void type of function, void type is easy to understand

void function(){}

see this bracket {
think of that as going up the elevator 1 level

think of this } as coming down 1 level

have you ever seen this in a code
a lot of these }}}}}}}}}}

heres a reason you might

Inserted Code

void function()
{
   if ()
      {
      if ()
         {
         if ()
            {

            }
         }
      }
}

basically i just went up about 3 levels, if i dont come back down, il get a error

most often a newbie will have great trouble if just 1 of } is missing

#3
Dec 1, 2009 9:19pm Dec 1, 2009 9:19pm

tomhliles
| Additional Username | Joined Dec 2006 | 163 Posts

check this out

if (something)

notice theres no brackets?

what will happen now, is that rule will apply to what ever is next, and only that one single next thing

if (something)blah=0;

or

if (something)
blah=0;

you should be noticing by now that spaces do not matter

ok check this out

if (something){blah=0;}

whats the difference?

the difference is that the rule now applies to everything inside the {brackets}

if (something){blah=0;blah2=0;blah3=0;blah4=0;}

we can also add rules inside rules
check this out

if (something){blah=0;blah2=0;blah3=0;blah4=0;if (something2)blah5=0;}

i can put that anywhere

if (something){if (something2)blah5=0;blah=0;blah2=0;blah3=0;blah4=0;}

in this example, if something is true, all is set to 0 exept for the first thing after something2
regardless if its before or after the other stuff

so basically all the blah's were set to 0 if something is true, but blah5 needs both rules to be true, or its not changed

#4
Dec 1, 2009 9:39pm Dec 1, 2009 9:39pm

tomhliles
| Additional Username | Joined Dec 2006 | 163 Posts

youv been seeing alot of these ;

that must end things, if 1 of them is missing, you will get a error

if is a statement, were gonna just stick to it for a while

we can accomplish a lot with just the if statement

next thing is the variables, for now, we will declare them at the very top, if we put them at the top, we can use them anywhere, if we declare them in a function, we can only use them in a function

if the variable is declared inside the function, its a local variable, meaning it can only be used inside that function

if at the top, its a global variable

heres the diferent types of variables

bool this is a true/false type
int this is a whole number, integer, like the number 1
double this can have decimals, like 0.01
color this is a color, like Red
string this is text
datetime this is a int but in date time format

now, lets declare a variable at the top
for the sake of this tutorial, open metaeditor
in the file menu select new, create a new ea
i named mine tutorial_ea

now at the top
lets add a variable

iml put this at the top
int blah;

i declared it as a integer
i decided not to give it a value, so the returned value is Null
which means nothing, remember 0 is something, so null isnt even 0

if i wanted to give it a value, i would do this
int blah=0;

if i wanted this to be variable, that can be edited in the ea properties, i would add extern to it
extern int blah=0;

since theres no extern, this variable will not show up in the ea properties

heres my ea so far

Inserted Code

//+------------------------------------------------------------------+
//|                                                  tutorial_ea.mq4 |
//|                                   Copyright © 2009, Thomas Liles |
//|                                       http://www.some_site.com   |
//+------------------------------------------------------------------+
#property copyright "Copyright © 2009, Thomas Liles"
#property link      "http://www.some_site.com"
int blah;
//+------------------------------------------------------------------+
//| expert initialization function                                   |
//+------------------------------------------------------------------+
int init()
  {
//----
   
//----
   return(0);
  }
//+------------------------------------------------------------------+
//| expert deinitialization function                                 |
//+------------------------------------------------------------------+
int deinit()
  {
//----
   
//----
   return(0);
  }
//+------------------------------------------------------------------+
//| expert start function                                            |
//+------------------------------------------------------------------+
int start()
  {
//----
   
//----
   return(0);
  }
//+------------------------------------------------------------------+

#5
Dec 1, 2009 10:13pm Dec 1, 2009 10:13pm

tomhliles
| Additional Username | Joined Dec 2006 | 163 Posts

im trying to think of something we can make this ea do
iv decided to add a function that counts orders

iml have to go into the for operator to do this

the for operator will loop until the condition becomes false

Inserted Code

  for(int i=OrdersTotal();i>=0;i--)
 {
    OrderSelect(i, SELECT_BY_POS);

 }

basically, i said i is a int type, it equals the total orders, if i >0, the code is ran, and i = i-1

if total orders = 0
the code is not ran, everything {in the brackets is skipped}

i see the opportunity to explain a few things here

for starter
== equals
!= does not equal
> is greater
< is lesser
>= is equal or greater
<= is equal or lesser

earlier i showed
if (something)

lets assume this is a bool type (boolean)
which is true or false

theres multiple ways i can ask if this is true
all giving the same results

if (something)
if (something==true)
if (something!=false)
if (something!=0)
if (something==1)
if (something>0)

i should point out, bool is a integer, 0 means false, 1 means true

heres some ways i can ask if its false

if (!something)
if (something==false)
if (something!=true)
if (something!=1)
if (something==0)
if (something<1)

my preferred method for true is
if (something)

my preferred method for false is
if (!something)

now back to this
for(int i=OrdersTotal();i>=0;i--)

see the i--

that means subtract 1 from i

i++ means add 1 to i

you could do this
i=i-1;

or

i=i+1;

wel get deep in the math later

lets view this another way

for
(
int i=OrdersTotal();
i>=0;
i--
)

for(int i=OrdersTotal();i>=0;i--)
{
if i is above 0, this areah is reached
}

i like my variables to be global
in order to count the orders, we must create them

put this at the top

int buys,sells;

put this inside the start function

Inserted Code

buys=0;
sells=0;
  for(int i=OrdersTotal();i>=0;i--)
 {
    OrderSelect(i, SELECT_BY_POS);
    if ( OrderType() == OP_BUY)  {buys=buys+1;}
    if ( OrderType() == OP_SELL )   {sells=sells+1;}
 }

its very important to reset buys and sells to 0 before you count the orders, otherwise theyl keep increasing every tick

heres what you should have now

Inserted Code

//+------------------------------------------------------------------+
//|                                                  tutorial_ea.mq4 |
//|                                   Copyright © 2009, Thomas Liles |
//|                                       http://www.some_site.com   |
//+------------------------------------------------------------------+
#property copyright "Copyright © 2009, Thomas Liles"
#property link      "http://www.some_site.com"
int blah;
int buys,sells;
//+------------------------------------------------------------------+
//| expert initialization function                                   |
//+------------------------------------------------------------------+
int init()
  {
//----
   
//----
   return(0);
  }
//+------------------------------------------------------------------+
//| expert deinitialization function                                 |
//+------------------------------------------------------------------+
int deinit()
  {
//----
   
//----
   return(0);
  }
//+------------------------------------------------------------------+
//| expert start function                                            |
//+------------------------------------------------------------------+
int start()
  {
//----
buys=0;
sells=0;
  for(int i=OrdersTotal();i>=0;i--)
 {
    OrderSelect(i, SELECT_BY_POS);
    if ( OrderType() == OP_BUY)  {buys=buys+1;}
    if ( OrderType() == OP_SELL ){sells=sells+1;}
 }
//----
   return(0);
  }
//+------------------------------------------------------------------+

#6
Dec 1, 2009 10:18pm Dec 1, 2009 10:18pm

tomhliles
| Additional Username | Joined Dec 2006 | 163 Posts

now the ea will know how many orders we have

id like to show you a diferent way, so were gonna move the code to outside the start()

at the very very bottom
add this

Inserted Code

void orders()
{

}

now cut n paste the code in the start()
and put it inside that function
inbetween the 2 brackets

you should have this

Inserted Code

void orders()
{
buys=0;
sells=0;
  for(int i=OrdersTotal();i>=0;i--)
 {
    OrderSelect(i, SELECT_BY_POS);
    if ( OrderType() == OP_BUY)  {buys=buys+1;}
    if ( OrderType() == OP_SELL ){sells=sells+1;}
 }
}

now in the start()
put this
orders();

heres what you should have

Inserted Code

//+------------------------------------------------------------------+
//|                                                  tutorial_ea.mq4 |
//|                                   Copyright © 2009, Thomas Liles |
//|                                       http://www.some_site.com   |
//+------------------------------------------------------------------+
#property copyright "Copyright © 2009, Thomas Liles"
#property link      "http://www.some_site.com"
int blah;
int buys,sells;
//+------------------------------------------------------------------+
//| expert initialization function                                   |
//+------------------------------------------------------------------+
int init()
  {
//----
   
//----
   return(0);
  }
//+------------------------------------------------------------------+
//| expert deinitialization function                                 |
//+------------------------------------------------------------------+
int deinit()
  {
//----
   
//----
   return(0);
  }
//+------------------------------------------------------------------+
//| expert start function                                            |
//+------------------------------------------------------------------+
int start()
  {
//----
orders();
//----
   return(0);
  }
//+------------------------------------------------------------------+
void orders()
{
buys=0;
sells=0;
  for(int i=OrdersTotal();i>=0;i--)
 {
    OrderSelect(i, SELECT_BY_POS);
    if ( OrderType() == OP_BUY)  {buys=buys+1;}
    if ( OrderType() == OP_SELL ){sells=sells+1;}
 }
}

weve just created a function that counts orders

#7
Dec 1, 2009 10:28pm Dec 1, 2009 10:28pm

tomhliles
| Additional Username | Joined Dec 2006 | 163 Posts

some things are pre defined, mt4 knows there value, such as things like this

Ordertype()
Accountbalance()

Bid
Ask
Close[0]
Open[0]

i completely taught my self with the help system in editor

lets say youd like to code a moving average
in a box to the right, type ima
all the indies start with i
isar
ima
irsi

youl find a detailed explanation, and even a example you can copy n paste into your ea

heres from the help file

double iMA( string symbol, int timeframe, int period, int ma_shift, int ma_method, int applied_price, int shift)
Calculates the Moving average indicator and returns its value.
Parameters:
symbol - Symbol the data of which should be used to calculate indicator. NULL means the current symbol.
timeframe - Timeframe. It can be any of Timeframe enumeration values. 0 means the current chart timeframe.
period - Averaging period for calculation.
ma_shift - MA shift. Indicators line offset relate to the chart by timeframe.
ma_method - MA method. It can be any of the Moving Average method enumeration value.
applied_price - Applied price. It can be any of Applied price enumeration values.
shift - Index of the value taken from the indicator buffer (shift relative to the current bar the given amount of periods ago).

Sample:
AlligatorJawsBuffer[i]=iMA(NULL,0,13,8,MODE_SMMA,PRICE_MEDIAN,i);

now i can copy the eample, edit it

iMA(NULL,0,50,0,MODE_SMA,PRICE_CLOSE,0);

#8
Dec 1, 2009 10:36pm Dec 1, 2009 10:36pm

tomhliles
| Additional Username | Joined Dec 2006 | 163 Posts

how to trouble shoot

if you ever get a error that says zero divided
or your ea just isnt doing what you expected

use the Print() feature

it will print in the journal, anything you want

example
Print("testing");

or print a value

Print(buys);

or value with text

Print("buys= ", buys);

another way, same results

Print("buys= "+buys);

try this, all 1 line of code

Print("buys= "+buys+" sells= "+sells);

or comma seperated

Print("buys= ",buys," sells= ",sells);

with the comma seperated, im printing 4 things

without comma seperation im printing 1

this can be handy, because your limited to, i think 64 things

without the commas i could make more

#9
Dec 1, 2009 10:45pm Dec 1, 2009 10:45pm

tomhliles
| Additional Username | Joined Dec 2006 | 163 Posts

lets add to the orders function
might as well improve it

first thing i see, i can make it look cleaner

Inserted Code

void orders()
{
buys=0;
sells=0;
  for(int i=OrdersTotal();i>=0;i--)
 {
    OrderSelect(i, SELECT_BY_POS);
    if ( OrderType() == OP_BUY)  
        {
        buys=buys+1;
        }
    if ( OrderType() == OP_SELL )
        {
        sells=sells+1;
        }
 }
}

all i did was add some spaces, were going to count other things, so wel need it to be easy to read

now, lets also count the lots of the opened orders

add this at the top, lots will be double type

double buy_lots,sell_lots;

now in our function, dont forget to reset them to 0
so add this

buy_lots=0;
sell_lots=0;

now to tally up the lots
heres what iv done

Inserted Code

void orders()
{
buys=0;
sells=0;
buy_lots=0;
sell_lots=0;
  for(int i=OrdersTotal();i>=0;i--)
 {
    OrderSelect(i, SELECT_BY_POS);
    if ( OrderType() == OP_BUY)  
        {
        buys=buys+1;
        buy_lots=buy_lots+OrderLots();
        }
    if ( OrderType() == OP_SELL )
        {
        sells=sells+1;
        sell_lots=sell_lots+OrderLots();
        }
 }
}

heres the whole code

Inserted Code

//+------------------------------------------------------------------+
//|                                                  tutorial_ea.mq4 |
//|                                   Copyright © 2009, Thomas Liles |
//|                                       http://www.some_site.com   |
//+------------------------------------------------------------------+
#property copyright "Copyright © 2009, Thomas Liles"
#property link      "http://www.some_site.com"
int blah;
int buys,sells;
double buy_lots,sell_lots;
//+------------------------------------------------------------------+
//| expert initialization function                                   |
//+------------------------------------------------------------------+
int init()
  {
//----
   
//----
   return(0);
  }
//+------------------------------------------------------------------+
//| expert deinitialization function                                 |
//+------------------------------------------------------------------+
int deinit()
  {
//----
   
//----
   return(0);
  }
//+------------------------------------------------------------------+
//| expert start function                                            |
//+------------------------------------------------------------------+
int start()
  {
//----
orders();
//----
   return(0);
  }
//+------------------------------------------------------------------+
void orders()
{
buys=0;
sells=0;
buy_lots=0;
sell_lots=0;
  for(int i=OrdersTotal();i>=0;i--)
 {
    OrderSelect(i, SELECT_BY_POS);
    if ( OrderType() == OP_BUY)  
        {
        buys=buys+1;
        buy_lots=buy_lots+OrderLots();
        }
    if ( OrderType() == OP_SELL )
        {
        sells=sells+1;
        sell_lots=sell_lots+OrderLots();
        }
 }
}

#10
Dec 1, 2009 10:54pm Dec 1, 2009 10:54pm

tomhliles
| Additional Username | Joined Dec 2006 | 163 Posts

your probably already getting good enough to add things on your own

lets add profit to the counting

at the top
add this to the doubles
profit

should look like this
double buy_lots,sell_lots,profit;

also reset it to 0
and heres what iv done

profit=(profit+OrderProfit())+OrderSwap();

notice the extra ()
the reason is, i added more than 3 math's

heres some examples

1+1+1

or

(1+1)+1

other examples

(1+1)+(1+1)*10

more...

((1+1)+(1+1)*10)/2

this can go on forever
if you do not use ()
the math will not turn out right

heres the ea now

Inserted Code

//+------------------------------------------------------------------+
//|                                                  tutorial_ea.mq4 |
//|                                   Copyright © 2009, Thomas Liles |
//|                                       http://www.some_site.com   |
//+------------------------------------------------------------------+
#property copyright "Copyright © 2009, Thomas Liles"
#property link      "http://www.some_site.com"
int blah;
int buys,sells;
double buy_lots,sell_lots,profit;
//+------------------------------------------------------------------+
//| expert initialization function                                   |
//+------------------------------------------------------------------+
int init()
  {
//----
   
//----
   return(0);
  }
//+------------------------------------------------------------------+
//| expert deinitialization function                                 |
//+------------------------------------------------------------------+
int deinit()
  {
//----
   
//----
   return(0);
  }
//+------------------------------------------------------------------+
//| expert start function                                            |
//+------------------------------------------------------------------+
int start()
  {
//----
orders();
//----
   return(0);
  }
//+------------------------------------------------------------------+
void orders()
{
buys=0;
sells=0;
buy_lots=0;
sell_lots=0;
profit=0;
  for(int i=OrdersTotal();i>=0;i--)
 {
    OrderSelect(i, SELECT_BY_POS);
    if ( OrderType() == OP_BUY)  
        {
        buys=buys+1;
        buy_lots=buy_lots+OrderLots();
        profit=(profit+OrderProfit())+OrderSwap();
        }
    if ( OrderType() == OP_SELL )
        {
        sells=sells+1;
        sell_lots=sell_lots+OrderLots();
        profit=(profit+OrderProfit())+OrderSwap();
        }
 }
}

#11
Dec 1, 2009 11:20pm Dec 1, 2009 11:20pm

tomhliles
| Additional Username | Joined Dec 2006 | 163 Posts

im going to code this ea in a way, that adding indicators is pretty much unlimited

a couple years ago, i ran into the problem of many conditions to concider

when i was novice (copy n paste n edit coder)
i couldnt code over 3 indies, because i though i had to cover every possibility of there combination

i finally came up with a way, i can add all th rules i want

i do not want to get to far ahead before i go over global variables

the reason is, the ea will get reset, by either mt4 being shut down, or the broker resets it
or the user switches the chart tf causing a reset

in order to avoid many issues, iv come up with my own way of naming the global variables

a global variable is not stored in memory for the ea, like other variables in the ea, im talking about a variable for mt4, that has nothing to do with the ea

Global variables of the client terminal should not be mixed up with variables declared in the global scope of the MQL4 program.

multiple indies, scripts, ea's can use the same global variable

these variables are stored, i think 60 days from last edit, or use, so theyl always be there, wel use them often

lets go over how i name them
heres a basic name
GlobalVariableCheck("name")

heres the way i name them
GlobalVariableCheck(AccountNumber()+WindowExpertName()+Symbol()+IsTesting())

the reason is, tester can change our variables, if we run a test, it can effect our live trading ea

im going to create a global variable, so we know if weve already traded the current bar

put this in the init()

Inserted Code

if (!GlobalVariableCheck(AccountNumber()+WindowExpertName()+Symbol()+IsTesting()))
   GlobalVariableSet(AccountNumber()+WindowExpertName()+Symbol()+IsTesting(),iBarShift(NULL,0,1));

ibarshift returns the open time of the bar specified
this is where i create the variable

now in deinit put this

Inserted Code

GlobalVariableDel(AccountNumber()+WindowExpertName()+Symbol()+1);

the reason is, to delete globals from testing

i forgot to mention
init is ran when the ea is applied to the chart, or you switch chart time frames, or the broker resets you
or you reset the ea

deinit is ran when the ea is removed, or reset

start is ran every tick, that the broker allows the ea to see

in the init, i set the global to ibarshift, back 1 bar

were going to add a trading function, even though theres no trading rules yet, wel add them later

at the top add this
string signal;

heres the code so far

Attached File(s)

tutorial_ea.mq4 2 KB | 573 downloads

#12
Dec 1, 2009 11:39pm Dec 1, 2009 11:39pm

tomhliles
| Additional Username | Joined Dec 2006 | 163 Posts

i just had a realy good ideah

heres the new plan

were gonna make this ea trade in tester, using scripts, which use global variables

that means during a visual mode test, we can drag n drop scripts to the chart to trade

wel finish the ea, then wel make some scripts
wel give this a option, so we can still add a automated trading strategy to the ea

wel make objects on the chart, so we can toggle everything during the test

the ea will also function live

lets create the trading function

at the very bottom, but before the orders function
put this
void trade()
{

}

now, in order to make this ea reliable, we need to handle errors, and requotes

lets add this to the function
int total_orders=buys+sells;

now we have this
void trade()
{
int total_orders=buys+sells;
}

heres what iv done

Inserted Code

void trade()
{
int total_orders=buys+sells;
if (signal=="buy")OrderSend(Symbol(),OP_BUY,0.01,Ask,3,NULL,NULL,NULL,NULL,0,CLR_NONE);
if (signal=="sell")OrderSend(Symbol(),OP_SELL,0.01,Bid,3,NULL,NULL,NULL,NULL,0,CLR_NONE);
orders();
if ((buys+sells)!=total_orders)signal="none";
}

as you can see, we must get our trade, or the ea will try forever each tick until we do

now in the start, where you put orders();
put trade(); just under that

notice how i also used orders(); inside the trade(); function

that way, after were supposed to trade, wel check to see that we did

theres alot of ways to accomplish that, this is my preferred way

heres the code so far

Attached File(s)

tutorial_ea.mq4 2 KB | 481 downloads

#13
Dec 1, 2009 11:59pm Dec 1, 2009 11:59pm

tomhliles
| Additional Username | Joined Dec 2006 | 163 Posts

now lets edit a few things, for starters, lets make the lot size show up in the ea properties

at the top, put this
extern double lots=0.01;

now in the ordersend function, replace 0.01 with lots
like this

Inserted Code

if (signal=="buy")OrderSend(Symbol(),OP_BUY,lots,Ask,3,NULL,NULL,NULL,NULL,0,CLR_NONE);
if (signal=="sell")OrderSend(Symbol(),OP_SELL,lots,Bid,3,NULL,NULL,NULL,NULL,0,CLR_NONE);

if you would like to see trading arrows drawn on the chart, replace CLR_NONE with a color name

like this

Inserted Code

if (signal=="buy")OrderSend(Symbol(),OP_BUY,lots,Ask,3,NULL,NULL,NULL,NULL,0,Blue);
if (signal=="sell")OrderSend(Symbol(),OP_SELL,lots,Bid,3,NULL,NULL,NULL,NULL,0,Red);

were not going to put in a stop loss, or a teke profit
the reason is, ecn brokers are not compatable with that
you can edit the sl, tp after the order is opened

im anxiouse to test this ea, so lets create a function, so that a script can tell the ea to trade

in the start, ad this just below orders();
check_signal();

heres the new function i made

Inserted Code

void check_signal()
{
if (GlobalVariableCheck("buy"))signal="buy";
if (GlobalVariableCheck("sell"))signal="sell";
}

now we must edit the trade() function
heres what i did

Inserted Code

void trade()
{
int total_orders=buys+sells;
if (signal=="buy")OrderSend(Symbol(),OP_BUY,lots,Ask,3,NULL,NULL,NULL,NULL,0,Blue);
if (signal=="sell")OrderSend(Symbol(),OP_SELL,lots,Bid,3,NULL,NULL,NULL,NULL,0,Red);
orders();
if ((buys+sells)!=total_orders)
   {
   signal="none";
   GlobalVariableDel("buy");
   GlobalVariableDel("sell");
   }
}

now, all we have to do to make this ea open a trade, is create a global variable with any value, long as the name matches

in editor, on the file menu, click new, create a script
iml name mine, tutorial_buy_script

in the start function of that script, put this
GlobalVariableSet("buy",1);

now we can test the ea

it worked flawless for me

run a test in visual mode, pause the test, drag the script to the chart, resume the test

the ea should open a buy

Attached File(s)

tutorial_ea.mq4 3 KB | 461 downloads

tutorial_buy_script.mq4 < 1 KB | 537 downloads

#14
Dec 2, 2009 12:13am Dec 2, 2009 12:13am

tomhliles
| Additional Username | Joined Dec 2006 | 163 Posts

now we need a sell script

we also need a close script

its unlimited the scripts we can make, from pending orders, to using a sl to calculate lot size

we can even build in risk to reward ratios

lets add a close function

while i was making the close function, i notices a error in my for loop i made earler

see the >=
for(int i=OrdersTotal();i>=0;i--)

should be this
for(int i=OrdersTotal();i>0;i--)

now back to the close
in the start after the other functions
add this
if (GlobalVariableCheck("close"))close_all();

now above that, after orders()
add this
if (GlobalVariableCheck("close")&&(buys+sells>0))GlobalVariableDel("close");

heres the close function

Inserted Code

void close_all()
{
  for(int i=OrdersTotal();i>0;i--)
 {
    OrderSelect(i, SELECT_BY_POS);
     if ( OrderSymbol()==Symbol())
     {
        if ( OrderType() == OP_SELL )  {OrderClose( OrderTicket(), OrderLots(), Ask, 0, Red );}
        if ( OrderType() == OP_BUY )   {OrderClose( OrderTicket(), OrderLots(), Bid, 0, Blue );}
     }
  }
}

Attached File(s)

tutorial_sell_script.mq4 < 1 KB | 509 downloads

tutorial_close_script.mq4 < 1 KB | 517 downloads

tutorial_ea.mq4 3 KB | 518 downloads

#15
Dec 2, 2009 12:14am Dec 2, 2009 12:14am

tomhliles
| Additional Username | Joined Dec 2006 | 163 Posts

this ea can now be used to trade, or test manual trading in tester

feel free to ask any questions

#16
Dec 2, 2009 12:41am Dec 2, 2009 12:41am

tomhliles
| Additional Username | Joined Dec 2006 | 163 Posts

i found a few dumb errors

you can compare this to yours, theres a error in both of the for's

and in the global variable delete just under orders();
in the start function

there fixed in this version

Attached File(s)

tutorial_ea.mq4 3 KB | 494 downloads

#17
Dec 2, 2009 11:53am Dec 2, 2009 11:53am

trustdom
| Joined Nov 2009 | Status: Trader | 45 Posts

Tom,
I am new programming in this language. I modified an EA an when try to compile it there is a message in the errors tab that says "Compiling 'tp 100 +40 D1[1].5_ca.mq4'...
It has been in this state for hours eventhough below says "0 error(s), 0 warning(s)". I would like to know if this is normal...

Thanks before hand,
Carlos

#18
Dec 2, 2009 3:01pm Dec 2, 2009 3:01pm

tomhliles
| Additional Username | Joined Dec 2006 | 163 Posts

that is normal

Quoting trustdom

Disliked

Tom,
I am new programming in this language. I modified an EA an when try to compile it there is a message in the errors tab that says "Compiling 'tp 100 +40 D1[1].5_ca.mq4'...
It has been in this state for hours eventhough below says "0 error(s), 0 warning(s)". I would like to know if this is normal...

Thanks before hand,
Carlos

Ignored

#19
Dec 4, 2009 10:15pm Dec 4, 2009 10:15pm

wolfe
| Joined Nov 2007 | Status: Trader | 43 Posts

I don't have a question tomhliles, I just want to commend you for making this tutorial.

I am also a self-taught coder. I only wish when I first started that I ran across a thread such as the one you are creating. You are providing a very useful service here for many people.

Thank you for being a great contributor to the community.

-wolfe

#20
Dec 4, 2009 11:50pm Dec 4, 2009 11:50pm

wieb
| Joined Aug 2009 | Status: Trader | 51 Posts

Quoting tomhliles

Disliked

feel free to ask any questions

Ignored

Thank you very much for starting this thread tomhliles.

I am sure this thread helping many of us who try to learn MQL coding.

But I am still confuse on function, why use void?

Inserted Code

void orders()
{
buys=0;
sells=0;
  for(int i=OrdersTotal();i>=0;i--)
 {
    OrderSelect(i, SELECT_BY_POS);
    if ( OrderType() == OP_BUY)  {buys=buys+1;}
    if ( OrderType() == OP_SELL ){sells=sells+1;}
 }
}

Why not int ?

Inserted Code

int orders()
{
buys=0;
sells=0;
  for(int i=OrdersTotal();i>=0;i--)
 {
    OrderSelect(i, SELECT_BY_POS);
    if ( OrderType() == OP_BUY)  {buys=buys+1;}
    if ( OrderType() == OP_SELL ){sells=sells+1;}
 }
}

MQL Editor Help stated "A function that does not return values must be void type"

The orders() function should be return total order values to start() function, but why use void which does not return any values?

I am just a beginner coder and confuse on this, please advice.

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