normalize double work sometime

[faustf]

hi i have  a big  script for this reason i past only a part , i notice  normilize  double  some time work some time  not  work anyone  have idea  why ?

 if (ctrlclick == 1)
                    {
                        int shift = iBarShift(Cross_Correlato, 0, dt);
                        Print("index of the bar for the time ", TimeToStr(dt), " is ", shift);
                        Print("NZD  ", iOpen(Cross_Correlato, 0, shift));
                        PrintFormat("Time=%s  Price=%G  =>  X=%d  Y=%d", TimeToString(dt), price, x, y);
                        FirstPriceVC = iOpen(Cross_Correlato, 0, shift);
                        FirstPriceVI=price;
                        
                        ObjectSetString(0,"ViPrimario",OBJPROP_TEXT,NormalizeDouble(FirstPriceVI, 4)); 
                        ObjectSetString(0,"ViCorrPrimario",OBJPROP_TEXT,NormalizeDouble(FirstPriceVC, 4));
                        PrimPercents=NormalizeDouble((((( FirstPriceVI-FirstPriceVC)/FirstPriceVC))*100),2);
                        ObjectSetString(0,"ViPercents",OBJPROP_TEXT,PrimPercents);
                       // Prezzo=price;
                    }

[William Roeder]

You used NormalizeDouble, It's use is usually wrong, as it is in your case.

1. Floating point has an infinite number of decimals, it's you were 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 (2013)

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

3. SL/TP (stops) need to be normalized to tick size (not Point) — code fails on non-currencies.
             On 5Digit Broker Stops are only allowed to be placed on full pip values. How to find out in mql? - MQL4 programming forum #10 (2011)

   And abide by the limits Requirements and Limitations in Making Trades - Appendixes - MQL4 Tutorial and that requires understanding floating point equality Can price != price ? - MQL4 programming forum (2012)

4. Open price for pending orders need to be adjusted. On Currencies, Point == TickSize, so you will get the same answer, but it won't work on non-currencies. So do it right.
             Trailing Bar Entry EA - MQL4 programming forum (2013)
             Bid/Ask: (No Need) to use NormalizeDouble in OrderSend - MQL4 programming forum (2012)

5. Lot size must also be adjusted to a multiple of LotStep and check against min and max. If that is not a power of 1/10 then NormalizeDouble is wrong. Do it right.
             (MT4 2013)) (MT5 2022))

6. MathRound() and NormalizeDouble() are rounding in a different way. Make it explicit.
             MT4:NormalizeDouble - MQL5 programming forum (2017)
             How to Normalize - Expert Advisors and Automated Trading - MQL5 programming forum (2017)

7. Prices you get from the terminal are already correct (normalized).

8. PIP, Point, or Tick are all different in general.
             What is a TICK? - MQL4 programming forum (2014)

[faustf]

but not  extist also free build  for other people  a  function that  work always ??,i  not  uderstund  why Metatrade create a  function for round up, and after some time not work , Is it so hard to create a function that always works_?

[William Roeder]

faustf #:  Is it so hard to create a function that always works_?

They work all the time.

How To Ask Questions The Smart Way. (2004)
          Don't rush to claim that you have found a bug.
Questions Not To Ask
          My program doesn't work. I think system facility X is broken.

It is almost always your code.

[Yashar Seyyedin]

NormalizeDouble(floor(FirstPriceVI/0.0001)*0.0001, 4)

This is how i would use it.

[Agent86]

faustf:
ObjectSetString

I am confused about why NormalizedDouble would even work in a String type ? 

Isn't this a string requirement ? 

ObjectSetString(0,"ViPrimario",OBJPROP_TEXT,NormalizeDouble(FirstPriceVI, 4))

vs


ObjectSetString(0,"ViPrimario",OBJPROP_TEXT,
DoubleToStr (FirstPriceVI, 4))

Pehaps I'm wrong but doesn't OjectSetString require this to be converted to a string ? 




https://docs.mql4.com/objects/objectsetstring

[William Roeder]

Agent86 #: Pehaps I'm wrong but doesn't OjectSetString require this to be converted to a string ?

And the double will be (implicitly). The text will be 1.23456700000000001. Not what is wanted. See #1.2.