Float to integer conversion

Question

I want to take the value from my slider and without rounding up, crop the decimals. So if I have a float value of 10.973. I want it in an integer as 10. I dont use negative values but if the slider value is between 0 and 1 id rather it round up. How would i make a statement doing the following?

Even if it's the default behavior, it could be helpful to state it explicitly. People who are new to a certain programming environment don't know the assumptions. — Willem Van Onsem, Sep 16 '13 at 22:02

score 1 · Accepted Answer · answered Sep 16 '13 at 21:50

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You should use:

f = (int)floorf(x);

floorf however will round to the lower integer so -2.79 will result in -3.

answered Sep 16 '13 at 21:50

Willem Van Onsem

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how would i round up on a positive number? – 4GetFullOf Sep 16 '13 at 22:33
`ceilf`. So `2.12` will result in `3`. But again `-3.98` will result in `-3` – Willem Van Onsem Sep 16 '13 at 22:34
can you give me an example of how ceilf is used? – 4GetFullOf Sep 16 '13 at 22:37
Simply replace `floorf` with `ceilf`: `f = (int)ceilf(x);` – Willem Van Onsem Sep 16 '13 at 22:39
I've found a post with the most common float-to-int operation: http://stackoverflow.com/a/6107681/67579 – Willem Van Onsem Sep 16 '13 at 22:40
f being my integer variable and x being my float variable? – 4GetFullOf Sep 16 '13 at 23:19
Yes. The mathematical notation (`f` being the result of a function `f(x)`) perhaps `i = (int) ceilf(f)` was a better option :s) – Willem Van Onsem Sep 16 '13 at 23:21

score 1 · Answer 2 · answered Sep 16 '13 at 21:55

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Just a simple integer cast would work.

int intVal = (int)floatVal;

answered Sep 16 '13 at 21:55

Jason Clardy

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how would i round up on a positive number – 4GetFullOf Sep 16 '13 at 22:34

score 0 · Answer 3 · answered Sep 16 '13 at 21:58

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A simple cast to integer should do:

int i = int(f)

If f is 10.973 i will be 10. If f is -10.973, i will be -10. A cast to int will simply truncate the decimal part.

answered Sep 16 '13 at 21:58

Thomas Nguyen

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How would i round up on a positive number? – 4GetFullOf Sep 16 '13 at 22:33
You have the brackets around the wrong part. Should be `int i = (int)f` – danielbeard Sep 16 '13 at 22:34

Float to integer conversion

3 Answers3