addition float values with 3 decimal points

Question

I have 2 float values as

A = 0.0306880000
B = 0.0396640000

When I use printf to print as "%5.3f", A value is printed as 0.031 and B values is printed as 0.040. When I add the two values together, I get the answer 0.070 (which is 0.0306880000 + 0.0396640000).

How do I include only 3 decimal points to be taken in to the addition so that the answer would be 0.071 (0.031 + 0.040).

That is not possible, in general, with floating point types. — 2501, Feb 21 '17 at 01:56
do you mean the answer should be 0.069 when i add the 0.0306880000 and 0.0396640000 do a printf with %5.3f? — anisha, Feb 21 '17 at 02:13
Possible duplicate of [C- Floating point precision](http://stackoverflow.com/questions/9577179/c-floating-point-precision) — MuertoExcobito, Feb 21 '17 at 02:23
@MuertoExcobito The post you flagged as a duplicate is related to the issue, but is in no way an actual duplicate. — 2501, Feb 21 '17 at 02:26

score -1 · Answer 1 · answered Feb 21 '17 at 03:49

-1

You should round the value of A and B using this macro:

#define ROUND3(number) ( (int)( (number) * 1000 + 0.5 ) / 1000.0 )

test code

answered Feb 21 '17 at 03:49

Divlaker

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This fail for many negative numbers, values outside the `int` range, values that round when adding 0.5 and some other cases. – chux - Reinstate Monica Feb 21 '17 at 04:11

addition float values with 3 decimal points

1 Answers1