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Java Programming [Archive] - Math.round
This topic has 6 replies on 1 page.

Posts:341
Registered: 03-06-12
Math.round  
Aug 9, 2004 7:21 AM



 
I found the function I want to use. But I am not sure how to use it.

I have a class called FtoC
and i return converstion of Fahrenheit to Celsius

class FtoC{public static double getTemp(double tempF){   return (5.0 * (tempF - 32.0) / 9.0);}}//end class FtoC


now i want to round the converstion so i use the Math.round function in my return
class FtoC{public static double getTemp(double tempF){   return Math.round(5.0 * (tempF - 32.0) / 9.0);//used Math.round}}//end class FtoC


so if i input my tempF as 40 F
i receive my answer as 4.0 converted to C
but i actually want a two decimal place display
so my return looks like 4.45

how do i set the Math.round fucntion to adjust for decimals places???
any suggestions???

thanks in advance annie :)
 

Posts:67
Registered: 3/13/02
Re: Math.round  
Aug 9, 2004 7:29 AM (reply 1 of 6)



 
Multiple input by 100, call Math.round(), and then divide the result by 100?
 

Posts:341
Registered: 03-06-12
Re: Math.round  
Aug 9, 2004 7:30 AM (reply 2 of 6)



 
public static double getTemp(double tempF){   R = Math.floor(R * 100.0 + 0.5) / 100.0;  R = Math.round(100.0 * R) / 100.0;  return Math.round(5.0 * (tempF - 32.0) / 9.0);}

im playing around with this now but its giving me an error about my class. I guess the R is hurting me!!!
 

Posts:341
Registered: 03-06-12
Re: Math.round  
Aug 9, 2004 7:32 AM (reply 3 of 6)



 
first the R should be tempF because that is what i call it, but im still getting a weird result???
 

Posts:24,036
Registered: 2/3/03
Re: Math.round  
Aug 9, 2004 7:34 AM (reply 4 of 6)



 
To format decimal numbers, look at the java.text.DecimalFormat class.
 

Posts:67
Registered: 3/13/02
Re: Math.round  
Aug 9, 2004 7:37 AM (reply 5 of 6)



 
Something like this should work, though I haven't tried it ...

tempF *= 100.0;tempF = Math.round(tempF);tempF /= 100.0; return tempF;
 

Posts:341
Registered: 03-06-12
Re: Math.round  
Aug 9, 2004 7:40 AM (reply 6 of 6)



 
tempF = (5.0 * (tempF - 32.0) / 9.0);
tempF *= 100.0;
tempF = Math.round(tempF);
tempF /= 100.0;
return tempF;

this works!!!!
cheers!
 
This topic has 6 replies on 1 page.