Anything related to converting a floating point number to and from other representations.
Questions tagged [floating-point-conversion]
290 questions
179
votes
1 answer
Why do ARM chips have an instruction with Javascript in the name (FJCVTZS)?
FJCVTZS is "Floating-point Javascript Convert to Signed fixed-point, rounding toward Zero". It is supported in Arm v8.3-A chips and later. Which is odd, because you don't expect to see JavaScript so close to the bare metal.
I can find explanations…
Tim Smith
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70
votes
9 answers
Why does C++ promote an int to a float when a float cannot represent all int values?
Say I have the following:
int i = 23;
float f = 3.14;
if (i == f) // do something
i will be promoted to a float and the two float numbers will be compared, but can a float represent all int values? Why not promote both the int and the float to a…
user4344762
43
votes
2 answers
printf format float with padding
The following test code produces an undesired output, even though I used a width parameter:
int main(int , char* [])
{
float test = 1234.5f;
float test2 = 14.5f;
printf("ABC %5.1f DEF\n", test);
printf("ABC %5.1f DEF\n", test2);
…
nabulke
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40
votes
5 answers
Format a float to n decimal places and no trailing zeros
I want to display a float with the entire integer part and up to two decimals for the fractional part, without trailing zeros.
http://play.golang.org/p/mAdQl6erWX:
// Desired output:
// "1.9"
// "10.9"
//…
Blaise
- 13,139
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32
votes
5 answers
How to convert a float into hex
In Python I need to convert a bunch of floats into hexadecimal. It needs to be zero padded (for instance, 0x00000010 instead of 0x10). Just like http://gregstoll.dyndns.org/~gregstoll/floattohex/ does. (sadly i can't use external libs on my platform…
user2339945
- 623
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31
votes
1 answer
Why does str(float) return more digits in Python 3 than Python 2?
In Python 2.7, repr of a float returns the nearest decimal number up to 17 digits long; this is precise enough to uniquely identify each possible IEEE floating point value. str of a float worked similarly, except that it limited the result to 12…
Mark Ransom
- 299,747
- 42
- 398
- 622
28
votes
4 answers
How to convert a float string to an integer in python 3
I'm new to the whole coding thing...so here goes.
Just trying to write a simple number guess game, but also do input validation. So that only integers are accepted as input. I've figured out how to weed out alphabetic characters, so I can convert…
corey
- 281
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23
votes
9 answers
Converting float to char*
How can I convert a float value to char* in C language?
boom
- 5,856
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- 96
23
votes
12 answers
Best way of checking if a floating point is an integer
[There are a few questions on this but none of the answers are particularly definitive and several are out of date with the current C++ standard].
My research shows these are the principal methods used to check if a floating point value can be…
P45 Imminent
- 8,319
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- 35
- 78
21
votes
6 answers
Size of int and float
I have a question about the ranges of ints and floats:
If they both have the same size of 4 bytes, why do they have different ranges?
atul
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20
votes
4 answers
how can I force division to be floating point in Go?
I have the following code snippet:
package main
import("fmt";"flag")
func main() {
var a = flag.Int("a",0,"divident")
var b = flag.Int("b",1,"divisor")
flag.Parse()
fmt.Printf("%f",*a / *b )
}
For -a 3 and -b 2 command line…
Croo
- 1,301
- 2
- 13
- 32
19
votes
2 answers
Half-precision floating-point arithmetic on Intel chips
Is it possible to perform half-precision floating-point arithmetic on Intel chips?
I know how to load/store/convert half-precision floating-point numbers [1] but I do not know how to add/multiply them without converting to single-precision…
Kadir
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18
votes
2 answers
What blocks implementation of std::to_chars and std::from_chars
According to https://en.cppreference.com/w/cpp/compiler_support#cpp17, no major vendor yet supports floating point versions of std::to_chars and std::from_chars. I understand that correctly formatting a floating point number is nontrivial, yet…
user877329
- 6,717
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16
votes
1 answer
Will int to double conversion round up, down or to nearest double?
Simple question: Will the conversion from an int, say 100, to a double "round" up or down to the next double or will it always round to the nearest one (smallest delta)?
e.g. for static_cast(100):
Which way will it cast if d2 < d1?
Bonus…
glades
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15
votes
9 answers
Limit floating point precision?
Is there a way to round floating points to 2 points? E.g.: 3576.7675745342556 becomes 3576.76.
jmasterx
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