Small Problem With a Maths Program

[Interista]

Program works grand except it gives looser numbers as answers, rather than exact.

I.e. it should add the three numbers and give the answer of 16.3
and it should multiply and subtract and give answer 118.24

Instead it gives 16.2999999xxxxxxxxx
and 118.23999999xxxxxx

How do I tighten it up?

public class VariableDifference
{
	public static void main (String[] args)
		{
			double num1=3.1f;
			double num2=6.2f;
			double num3=7.0f;
									
			double sum = num1+num2+num3;
			double sum1 = num1*num2*num3-num1-num2-num3;
						
			System.out.println("The variable sum contains the value " + sum);
			System.out.println("The variable difference contains the value " + sum1);
			
			System.exit(0);
		}
}

[KevinWorkman]

Sounds like a job for DecimalFormat or the printf method: PrintStream (Java Platform SE 6)

[Interista]

Ah right, I think I should be careful over that. My lecturer hasn't covered that yet so he might think I've been cheating!

[Baconator]

Ah right, I think I should be careful over that. My lecturer hasn't covered that yet so he might think I've been cheating!

I wouldn't consider it cheating if you went ahead and did some out of class research to learn more about programming. I'm taking AP Computer Science at my high school and I'm a full semester ahead of my other classmates since I have been teaching myself through YouTube, Google, and referring to later chapters in the book. Good luck though!