Confused about something in the D book relating to precision

[Ali Çehreli]

On 12/4/22 18:57, thebluepandabear wrote:

 > I am not understanding why Ali said there is a decimal mark if precision
 > is nonzero?
 >
 > How can a number have zero precision?

That "precision" is referring to how many digits are printed after the 
decimal mark in the formatted output.

 > "the required digits after the decimal mark, the number of which is
 > determined
 > by precision (default precision is 6)"

So, if we print with %e, we get 6 digits:

     enum f = 1.23456789;
     writefln!"%e"(f);

Prints

1.234568e+00

There are 6 digits after the decimal point.

Now 3 digits of precision:

     writefln!"%.3e"(f);

Prints

1.235e+00

Now 0 precision, where the decimal point will disappear:

     writefln!"%.0e"(f);

Prints

1e+00

 > Well double has a precision of 15

Different meanings for the same word...

 > I feel like this section was explained poorly and it's confusing.

I have to agree. Nobody really knows these by heart. Once you know 
what's available, you just come back and pick what you need for that 
occasion.

Ali