Converting a double to a long, then back to double?

Question

Does Converting a double to a long, then back to double, guarantees keeping the exact value to the left of the decimal point?

EDIT: Working with C++: Conversion is as follows:

double d_var = func();
long l_var = (long)d_var;
d_var = (double)l_var;

`2^53 + 1` is the smallest integer that cannot be represented by the `double` format. — Arc, Mar 25 '22 at 18:16

score 1 · Accepted Answer · answered Mar 22 '22 at 12:11

1

For every programming language I have worked with it will keep the value to the left of the decimal point.

answered Mar 22 '22 at 12:11

MaxVK

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score 0 · Answer 2 · answered Mar 22 '22 at 12:37

0

For typecast then the fractions are removed when casting, but for range then double can hold bigger numbers than long and therefore becomes something else during a typecast.

At least for common languages I can think of.

answered Mar 22 '22 at 12:37

Thomas Koelle

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Converting a double to a long, then back to double?

2 Answers2