Round only the decimal points to the nearest tens in Java like 1.17 to 1.20

Question

How can I round a given number, for example 1.17 to 1.20 not 1.0 or 2.0. I was trying to print a list of centimeters, feet and inches from 4 ft to 7 ft. I've got the centimeters, and feet part working but the inches part is not as intended.

Here is the function I use to generate the list and log the results

private void print() {
        final float oneInch = 2.54f;
        final float oneFt = 30.48f;
        final float end = oneInch * 12 * 7;
        float start = oneInch * 12 * 4;
        int cm;
        int ft;
        float in;
        StringBuilder sb = new StringBuilder();
        DecimalFormat decimalFormat = new DecimalFormat("#.##");
        decimalFormat.setRoundingMode(RoundingMode.HALF_UP);
        while (start <= end) {
            if (sb.length() > 0) {
                sb.replace(0, sb.length(), "");
            }

            cm = (int) start;
            sb.append(cm);
            sb.append(" cm, ");

            ft = (int) (start / oneFt);
            in = Float.valueOf(decimalFormat.format(start / oneFt - ft));
            if (in >= 1.0f) {
                ++ft;
                in = 0f;
            }
            sb.append(ft);
            sb.append(" ft ");
            if (in > 0) {
                sb.append(String.valueOf(in).replace("0.", ""));
            }
            start += oneInch;
            Log.i("measure", sb.toString());
        }
    }

Here is the logged values

121 cm, 4 ft
124 cm, 4 ft 08
127 cm, 4 ft 17
129 cm, 4 ft 25

it is printing as 4 ft 08, how can I print the inches part as whole numbers, like this?

121 cm, 4 ft
124 cm, 4 ft 1
127 cm, 4 ft 2
129 cm, 4 ft 3

Answer 1

Do not use Strings for numeric operations. When doing math, use math operators and math functions:

in = (start / oneFt - ft) * 12;

You don't need to round your numbers at all. Let the DecimalFormat do the rounding:

if (in > 0) {
    sb.append(decimalFormat.format(in));
}