CODEWITHSUNDEEP
javabit-manipulationbitwise-operators
kran
kran

Reputation: 135

abs function for float value in java

I need to create a function abs for float with bitwise operators, this function return float value.

I can't use < or >.

I try this 

(float)((int)f ^ ((int)f>>31)) - ((int)f>>31)

but for -2.5 value I get 2.0, it's not correct.

Can you help me?

Upvotes: 0

Views: 514

Answers (2)

Peter Lawrey
Peter Lawrey

Reputation: 533820

You can do this

float abs = Float.intBitsToFloat(Float.floatToIntBits(x) & 0x7FFFFFFF);

Upvotes: 3

Michael Krause
Michael Krause

Reputation: 4869

The most significant bit of a float is the sign bit. So... you should be able to use the bitwise & operator to clear that bit to get the absolute value.

Use this as your mask to bitwise and with your value:

0x7fffffff

Upvotes: 2

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