Strange MT4 output - mql bug ?

[[Deleted]]

Hi,

I wrote a simple script that is supposed to calculate a distance (in pips) between moving average and current price.

int start()

{

Alert("++++++++++++++++++");

Alert("Digits: ", Digits);

Alert("Bid: "+(Bid));

Alert("MA: ",+(iMA(NULL, 0, 3, 1, MODE_LWMA, PRICE_CLOSE, 0)));

if (Bid > iMA(NULL, 0, 3, 1, MODE_LWMA, PRICE_CLOSE, 0))

{

x = Bid - iMA(NULL, 0, 3, 1, MODE_LWMA, PRICE_CLOSE, 0);

Alert("Bid - MA = ", x);

}

if (Bid < iMA(NULL, 0, 3, 1, MODE_LWMA, PRICE_CLOSE, 0))

{

x = iMA(NULL, 0, 3, 1, MODE_LWMA, PRICE_CLOSE, 0) - Bid;

Alert("MA - Bid = ", x);

}

y = MathPow(10, Digits);

Alert("10 to power of ", Digits, " = ", y);

z = x * y;

Alert(x, " * ", y, " = ", z);

return(0);

}

Example outputs:

Digits: 4

Bid: 1.08420000

MA: 1.0749

MA - Bid = 0.0093

10 to power of 4 = 10000

0.0093 * 10000 = 92.8333

Digits: 5

Bid: 1.53059000

MA: 1.53

Bid - MA = 0.000 6

10 to power of 5 = 100000

0.0006 * 100000 = 59

How comes 0.0093 * 10000 equals 92.8333 ? Should be 93.

How comes 0.0006 * 100000 equals 59 ??

This is not a single case, almost always calculation is wrong...

Can someone explain what does it happen ? Is it a mql4 error or am I missing something?

[JC]

okt:

[...] This is not a single case, almost always calculation is wrong...

Can someone explain what does it happen ? Is it a mql4 error or am I missing something?

This sounds like an issue to do with arithmetic involving double values - for one of the many previous discussions of this issue, see https://www.mql5.com/en/forum/117138. In essence, MT4 is using more digits of precision than you're seeing in your alerts.

[gordon]

I also recommend you read this -> Articles -> Features -> Working with Doubles in MQL4