Question

It’s been quite a while since I last used D Programming Language, and now I’m using it for some project that involves scientific calculations.

I have a bunch of floating point data, but when I print them using writefln, I get results like: 4.62593E-172 which is a zero! How do I use string formatting % stuff to print such things as 0?

Right now I’m using a hack:

    if( abs(a) < 0.0000001 )         writefln(0);     else         writefln(a); 

it does the job, but I want to do it using the formatting operations, if possible.

UPDATE

someone suggested writefln('%.3f', a) but the problem with it is that it prints needless extra zeros, i.e. 0 becomes 0.000 and 1.2 becomes 1.200
Can I make it also remove the trailing zeros?

Answer 1

Short answer: This can’t be done with printf format specifiers.

Since D uses the same formatting as C99’s vsprintf(), you find your answer in this thread: Avoid trailing zeroes in printf()