Counting the number of decimal places in pascal

Question

I just started studying pascal and I have to do a pascal program as homework. I made it but I don\'t know how to count the number of decimal places in a real number<

Answer 1

The Format() function is normally used in situations like this.

WriteLn(Format('%*.*f', [0, dec, your_real_number]));

*.* is interpreted as total_characters.decimal_digits. Passing zero for the first means that width is adjusted according to how large your real is. The number of decimals can be a variable (dec), which you can adjust to your specification.

---

Update:

You mention that you want an exact representation of a float with respect to the number of decimals.

As mentioned in my comment, most floating point values does not have a finite number of decimals. And most decimal fractions cannot be represented by a binary type.

There are some libraries that can handle floating point values of arbitrary size. See TBigFloat for example. There is a formatting routine that can strip redundant zeroes from a decimal float.

---

Still, there is a possibility to remove trailing zeroes by using the general format specifier:

WriteLn(Format('%g',[your_real_number]));

You can specify the width and the number of significant digits as well.