Subtraction different

[alaylwint]

I am strange with mql4.

Now I subtract two value Bid - MydoubleVar . But Result is not look like from calculator result.

eg..

Bid value is 1.01424
MydoubleVar is 1.01427

If I used like that

MessageBox(Bid - MydoubleVar);

Message Box replied that -2.99999999999

Normal Calculator result is -0.00003

Why are they different.

Thanks

[Carl Schreiber]

alaylwint:

I am strange with mql4.

Now I subtract two value Bid - MydoubleVar . But Result is not look like from calculator result.

eg..

Bid value is 1.01424
MydoubleVar is 1.01427

If I used like that

MessageBox(Bid - MydoubleVar);

Message Box replied that -2.99999999999

Normal Calculator result is -0.00003

Why are they different.

Thanks

Doubles aren't as precise as integers the reason is explained here.

[William Roeder]

1. 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
2. If you want the value displayed reasonably, convert it to a string.