IsNegative(double) ?

[Funkymatt]

Is there an IsNegative function of any sort? If no, what is the best way to determine a doubles positive or negative value?

I suppose I could always cast to a string and then read the leftmost character. If it's "-" then negative and if not, it's positive (assuming leading zeros trimmed). But I think there has to be a better way? Anyone?

 

[maxpower1]

this may answer your question.

thread269-580099

~za~
You can't bring back a dead thread!

 

[richardbergquist]

Sounds like you are getting bogged down in the use of the Double object vs the double primitive.

If you are using the Double object then compareTo() is worth a look for your use.

See if this snippet helps shed light :

public class Scratcher
{
public Scratcher()
{
}

public void cycle1()
{
double d1 = 56D;
double d2 = -546D;
double d3 = 0D;

Double D1 = new Double(d1);
Double D2 = new Double(d2);
Double D3 = new Double(d3);

printDouble(d1);
printDouble(d2);
printDouble(d3);

printDouble(D1);
printDouble(D2);
printDouble(D3);
}

public void printDouble(double d)
{
if (d > 0D)
System.out.println(d + " is > 0"
else if (d < 0D)
System.out.println(d + &quot; is < 0&quot;
else if (d == 0D)
System.out.println(d + &quot; is == 0&quot;
}

public void printDouble(Double d)
{
if (d.compareTo(new Double(0D)) > 0)
System.out.println(d.toString() + &quot; is > 0&quot;
else if (d.compareTo(new Double(0D)) < 0)
System.out.println(d.toString() + &quot; is < 0&quot;
else if (d.compareTo(new Double(0D)) == 0D)
System.out.println(d.toString() + &quot; is == 0&quot;
}
public static final void main(String[] args)
{
Scratcher me = new Scratcher();
me.cycle1();
}//eom

}//eoc

Will give as output :

56.0 is > 0
-546.0 is < 0
0.0 is == 0
56.0 is > 0
-546.0 is < 0
0.0 is == 0


RjB.