Order Lotage

[prg_mt4]

Hello Friends, 

I'm surprised by one thing 

I use this code: 

double   min_lot     = SymbolInfoDouble(_Symbol,SYMBOL_VOLUME_MIN);
double   max_lot     = SymbolInfoDouble(_Symbol,SYMBOL_VOLUME_MAX);
int      lotdigits   = (int) - MathLog(SymbolInfoDouble(_Symbol, SYMBOL_VOLUME_STEP));
double   lots        = NormalizeDouble(_lotcalculation, lotdigits);

when my order lots is 0.07 (Only this number!!) i get Print from lots and it is 0.070000000001 

My order open with 0.07 but when I get and Print  order lotage by 

OrderGetDouble(ORDER_VOLUME_INITIAL)   

I see lotage is 0.070000000001 . 

Please not that it accord only for 0.07 lots!!

Do you have any Idea about this ?

[prg_mt4]

Unbelievable!!! 

The result of this code is 0.0700000000001

string lottDD;
void OnTick(void)
  {
  lottDD=StringToDouble(0.07);
   Print(lottDD);
  }

[Ehsan]

prg_mt4:

Hello Friends, 

I'm surprised by one thing 

I use this code: 

when my order lots is 0.07 (Only this number!!) i get Print from lots and it is 0.070000000001 

My order open with 0.07 but when I get and Print  order lotage by 

I see lotage is 0.070000000001 . 

Please not that it accord only for 0.07 lots!!

Do you have any Idea about this ?

Floating point numbers aren't 100% accurate and 0.07 doesn't have an exact representation in floating point.

[William Roeder]

prg_mt4: I see lotage is 0.070000000001 . 
prg_mt4: The result of this code is 0.0700000000001

Floating point has infinite number of decimals, it's your not understanding floating point and that some numbers can't be represented exactly. (like 1/10.)
          Double-precision floating-point format - Wikipedia, the free encyclopedia

See also The == operand. - MQL4 programming forum

Print out your values to the precision you want with DoubleToString - Conversion Functions - MQL4 Reference.

[prg_mt4]

William Roeder:

Floating point has infinite number of decimals, it's your not understanding floating point and that some numbers can't be represented exactly. (like 1/10.)
          Double-precision floating-point format - Wikipedia, the free encyclopedia

See also The == operand. - MQL4 programming forum

Print out your values to the precision you want with DoubleToString - Conversion Functions - MQL4 Reference.

Thank you for your answer 

I used  MathFloor(x/lotStep)*lotStep

but result is 0.0700000001

Actually I don't know how can I create 0.07 

this is very bad problem for me . EA close my order immediately because my order lotage is more than acceptable risk management .

Could you exactly tel me how can I make 0.07 lotage in my code 

Thank you very very much 

[William Roeder]

What part of "some numbers can't be represented exactly" was unclear?

If you loose the extra $0.000000000001 is that unacceptable?

[prg_mt4]

William Roeder:

What part of "some numbers can't be represented exactly" was unclear?

If you loose the extra $0.000000000001 is that unacceptable?

Hello Williams 

this issue solved with this formula :

if(P_lots-Lots_F[sd_1]>-0.0000001) {close all positions}

It's Ok now . 

Thank you for your help 👍👍

[prg_mt4]

William Roeder:

What part of "some numbers can't be represented exactly" was unclear?

If you loose the extra $0.000000000001 is that unacceptable?

Dear william, can you answer to my question in this page ?

https://www.mql5.com/en/forum/323372

[Pavel Shutovskiy]

Do not use the NormalizeDouble function to calculate lots

double volumeStep = SymbolInfoDouble(_Symbol, SYMBOL_VOLUME_STEP);
double lot = round(_lotcalculation / volumeStep) * volumeStep;

This option will work correctly