Using the ceil() function more advanced

Question

I am aware of what the ceil function does, it rounds numbers up. So; 1.3 to 2.0 and 5.9 to 6.0. But I want it to round up with steps of 0.5. So; 1.3 to 1.5 and 5.9 to 6.0. Is this possible? Thanks!!!

Note: Once `|x|` exceeds about `power(2, DBL_MANT_DIG -1)`, `double` loses the ability to round to the nearest 0.5. — chux - Reinstate Monica, Apr 06 '14 at 18:00

Martin R · Accepted Answer · 2014-04-06T17:45:09.003

4

y = ceil(x * 2.0)/2.0;

should do what you need:

x     x*2.0   ceil(x*2.0)  y
------------------------------
1.3    2.6     3.0         1.5
1.6    3.2     4.0         2.0
5.9   11.8    12.0         6.0

edited Apr 06 '14 at 17:45

answered Apr 06 '14 at 17:40

Martin R

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Clever! I can't believe I didn't figure that out for myself! Thanks! – Vince Apr 06 '14 at 21:18

Using the ceil() function more advanced

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