Sign functions ( abs, neg, sign )

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Sign functions ( abs, neg, sign )

The sign functions in Logo are used when you need to examing or change the sign of a number.

If you say the function abs, then Logo will remove the sign of a value and convert it ito a positive number.

The other function is neg and it negates a number - if it is positive, after applying the action the result will be negative, and vice versa.

Actually, negating a value is the same as subtracting it from 0.
	print abs 20 ; 20
	print abs -15 ; 15
	print neg 10 ; -10
	print neg -7 ; 7
Both abs and neg return the same numbers, but eventually with changed signs.

In order to see what the sign of a value is, you may ask the function sign.

It will return -1 if a value is negative, +1 if it is positive, and 0 if it is zero.
	print sign -3 ; -1
	print sign 0 ; 0
	print sign 4 ; 1

Mathematical functions (guide) Exponential functions (sqrt, exp, logn )