How can I verify if a double number have a decimal part?

[pieroim]

Example:

EURUSD price: 1.22375

it40cash price: 23638

these numbers are both double, but the first has a decimal part, the second not.

Is there a way to verify if a number have a decimal part?

Thank's

Piero

[Icham Aidibe]

pieroim:

Example:

EURUSD price: 1.22375

it40cash price: 23638

these numbers are both double, but the first has a decimal part, the second not.

Is there a way to verify if a number have a decimal part?

Thank's

Piero

You could for example convert it into a string and search for the "." 

EDIT : not with strings cause it adds a .0 to an integer. Much more simply actually : 

if (MathRound(price)==price) { printf("**** yeeepeeee no digits!"); }  

[nicholish en]

pieroim:

Example:

EURUSD price: 1.22375

it40cash price: 23638

these numbers are both double, but the first has a decimal part, the second not.

Is there a way to verify if a number have a decimal part?

Thank's

Piero

The CDouble library has a function to get the number of Digits.

#include <Double.mqh>
void OnStart()
{
//---
   double number = 0.1234567;
   printf("The number of digits in %.10f is %d", number, CDouble::GetDigits(number));
  
}

//The number of digits in 0.1234567000 is 7

[pieroim]

converting with the string I tried yesterday but it does not work as you said.

I was looking for a library like Double.mqh, very good!

Thanks

Piero

[pieroim]

Hi

I have a problem with the Double library.

----------------------------------------

bool Verifica(double prezzo, int decimali, int button)

  {

//verifica decimali

      int lungh2 = CDouble::GetDigits(prezzo);

--------------------------------------

if "prezzo" came from the function "SymbolInfoDouble(Symbol, SYMBOL_BID)" where Symbol is EUSUSD, I have that lungh2 = 16 as result.

But the result would be 5.. 

[nicholish en]

pieroim:

Hi

I have a problem with the Double library.

----------------------------------------

bool Verifica(double prezzo, int decimali, int button)

  {

//verifica decimali

      int lungh2 = CDouble::GetDigits(prezzo);

--------------------------------------

if "prezzo" came from the function "SymbolInfoDouble(Symbol, SYMBOL_BID)" where Symbol is EUSUSD, I have that lungh2 = 16 as result.

But the result would be 5.. 

You should only be using the tick size for prices. 

   CDouble eurusd_prices(PRECISION_TICK_SIZE,"EURUSD");
   eurusd_prices = SymbolInfoDouble("EURUSD",SYMBOL_BID);
   double step = eurusd_prices.Step();
   int digits = eurusd_prices.Digits();

[pieroim]

Great work!!

Thank's

Piero

[Darwinex]

pieroim:

Example:

EURUSD price: 1.22375

it40cash price: 23638

these numbers are both double, but the first has a decimal part, the second not.

Is there a way to verify if a number have a decimal part?

Thank's

Piero

This is possible to do entirely in MQL too, using the MathMod() function with a divisor of 1:

This is the MathMod() function spec:

double  MathMod(
   double  value,      // dividend value
   double  value2      // divisor value
   );

--

Here's a quick little function to test the values you've mentioned:

bool hasDecimal(double num)
{
   if(MathMod(num, 1) != 0)
   {
      Print(num + " -> has decimal places.");
      return(true);
   }
   
   Print(num + " -> does NOT have decimal places.");
   return(false);
}

Results:

hasDecimal(1.22375);

2018.01.25 12:14:48.679 TestBench EURUSD,H1: 1.22375 -> has decimal places.

hasDecimal(23638.0); // With ".0" for sake of completeness.

2018.01.25 12:14:48.679 TestBench EURUSD,H1: 23638 -> does NOT have decimal places.

hasDecimal(23638); // Without any decimal point.

2018.01.25 12:14:48.679 TestBench EURUSD,H1: 23638 -> does NOT have decimal places.

--

Hope this proves useful.

[William Roeder]

I wouldn't use MathMod. There are known problems with it due to floating point rounding. Doubles are rarely equal.
          The == operand. - MQL4 and MetaTrader 4 - MQL4 programming forum

bool isInt(double d){       return MathAbs(d - int(d) ) < DBL_EPSILON; }
bool hasFraction(double d){ return !isInt(d);                          }

[Alain Verleyen]

whroeder1:
I wouldn't use MathMod. There are known problems with it due to floating point rounding.

...

For reference about MathMod issue https://www.mql5.com/en/forum/143605#comment_3627665

[Darwinex]

Alain Verleyen:
For reference about MathMod issue https://www.mql5.com/en/forum/143605#comment_3627665

Interesting.. the example in the earlier post was a trivial on-the-fly demo, but thank you very much for pointing this issue out with MathMod() - noted!