[unnah]

Since such algorithms were developed in the 1990's, nowadays you can expect your language's standard library to use them for float-to-decimal and decimal-to-float conversions. So all you need to do in code is to print the float without any special formatting instructions, and you'll get the shortest unique decimal representation.

[lifthrasiir]

Except that C specifies that floating point numbers should be printed in a fixed precision (6 decimal digits) when no precision is given. Internally they do use some sort of float-to-decimal algorithms [1], but you can't get the shortest representation out of them.

[1] Some (e.g. Windows CRT) do use the shortest representation as a basis, in which case you can actually extract it with large enough precision (where all subsequent digits will be zeros). But many libcs print the exact representation instead (e.g. 3.140000000000000124344978758017532527446746826171875 for `printf("%.51f", 3.14)`), so they are useless for our purpose.

[unnah]

Ok, you got me there. Looks like they fixed that in C++17 with std::to_chars. https://en.cppreference.com/w/cpp/utility/to_chars.html

[Sharlin]

That's what the %g format specifier is for.

  printf("%f\n", 3.14); // 3.140000
  printf("%g\n", 3.14); // 3.14