elisp: Floating-Point Type
2.3.2 Floating-Point Type
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Floating-point numbers are the computer equivalent of scientific
notation; you can think of a floating-point number as a fraction
together with a power of ten. The precise number of significant figures
and the range of possible exponents is machine-specific; Emacs uses the
C data type ‘double’ to store the value, and internally this records a
power of 2 rather than a power of 10.
The printed representation for floating-point numbers requires either
a decimal point (with at least one digit following), an exponent, or
both. For example, ‘1500.0’, ‘+15e2’, ‘15.0e+2’, ‘+1500000e-3’, and
‘.15e4’ are five ways of writing a floating-point number whose value is
1500. They are all equivalent.
Numbers, for more information.
Info Catalog
elisp: Integer Type
elisp: Programming Types
elisp: Character Type