CODEWITHSUNDEEP
c++
Tom Tom
Tom Tom

Reputation: 1209

Get exponent from a scientific notation

How do we extract the exponent and sign from a "scientific" notation?

If we print a double value with printf("%lf %e") it shows par ex.:

   normal   scientific
   ------   ----------
   -888.3   -8.88e2    
    1.23     1.23e0    
    3.001    3.1e-1

The solution pointed in How to get Exponent of Scientific Notation in Matlab

x = floor(log10(N))

works only for positive values N. With -N it shows -nan(ind). Obviously Log10() with negatie value is not allowed.

Upvotes: 0

Views: 1176

Answers (1)

ForceBru
ForceBru

Reputation: 44838

You don't care about the sign of the number, you need the exponent only, so you can get rid of the sign safely:

log10(abs(N))

Where abs returns the absolute value of N, which is always non-negative and thus can be used as an argument to log10.

Upvotes: 2

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