# Area of a triangle (using 2 extra methods) error help

• September 12th, 2010, 02:52 PM
SilentPirate
Area of a triangle (using 2 extra methods) error help
EDITED..

Oke, I managed to sort everything out, except, it does not calculate the area in area() method:

Code :

```[COLOR="Red"]public static double area(double side1, double side2, double side3, double areaTri)[/COLOR] { double s = (side1 + side2 + side3)/2; areaTri = Math.sqrt(s*(s - side1)*(s - side2)*(s - side3));   //Returns to main() and should print out the last statement with the area return areaTri; }```

Updated Code:
Code :

```//Calculate the area of a triangle   import java.util.Scanner; import static java.lang.Math.*;   [COLOR="Lime"]public class MyTriangle[/COLOR] { [COLOR="Red"]public static void main(String[] args)[/COLOR] { double areaTri=0; Scanner input = new Scanner(System.in);   System.out.print("Enter the size of the first side: "); double side1 = input.nextDouble();   System.out.print("Enter the size of the second side: "); double side2 = input.nextDouble();   System.out.print("Enter the size of the third side: "); double side3 = input.nextDouble();   isValid(side1,side2, side3, areaTri);   System.out.println(""); System.out.println("The area of the triangle is "+ areaTri); } //Check if the sum of side1 and side2 is greater than side3 and if not returns false //If true calls on method area() [COLOR="Red"]public static boolean isValid(double side1, double side2, double side3, double areaTri)[/COLOR] { if(side1 * side2 > side3) { area(side1,side2,side3, areaTri); return true; } else { System.out.println("The input is invalid!"); return false; } } //calculates area of the triangle assuming conditions are met at method isValid() [COLOR="red"]public static double area(double side1, double side2, double side3, double areaTri)[/COLOR] { double s = (side1 + side2 + side3)/2; areaTri = Math.sqrt(s*(s - side1)*(s - side2)*(s - side3)); return areaTri; } }```
• September 12th, 2010, 04:54 PM
Norm
Re: Area of a triangle (using 2 extra methods) error help
Quote:

, it does not calculate the area in area() method:
What is it supposed to do in that method?
Do you have a question?

If you need help debugging your code, I suggest that you separate out all the subexpressions in the sqrt() method call and print them out to see if they are computing to the values you expect.
• September 12th, 2010, 05:14 PM
SilentPirate
Re: Area of a triangle (using 2 extra methods) error help
I managed to fix it in the main():

From:

Code :

`System.out.println("The area of the triangle is "+ areaTri);`

To:

Code :

`System.out.println("The area of the triangle is "+ area(side1,side2,side3,areaTri));`

This solved the problem and lead to another. How do I round it off to 1 decimal place. Right now the output would look something like this:

0.7261843774138906
• September 12th, 2010, 05:18 PM
Norm
Re: Area of a triangle (using 2 extra methods) error help
Quote:

How do I round it off to 1 decimal place
A couple of ways
The printf() has formatting strings
The DecimalFormat class will format a number.
• September 12th, 2010, 05:39 PM
SilentPirate
Re: Area of a triangle (using 2 extra methods) error help
I decided to use printf() since I'm more familiar with it, but it doesnt seem to work the same:

In C this would normally work:
Code :

`printf("The area of the triangle is %0.1f", area(side1,side2,side3,areaTot));`

I get a format specifier error in java when running:
Code :

`System.out.printf("The area of the triangle is %0.1f", area(side1,side2,side3,areaTot));`
• September 12th, 2010, 05:45 PM
Norm
Re: Area of a triangle (using 2 extra methods) error help
Have you looked up the error message to see what it means? It could tell you what the problem is.
• September 12th, 2010, 05:49 PM
SilentPirate
Re: Area of a triangle (using 2 extra methods) error help
I know what it means...the format specifier "%0.1f" doesnt work, my question is how could I interprate this into java to show a single decimal place.
• September 12th, 2010, 05:52 PM
Norm
Re: Area of a triangle (using 2 extra methods) error help
Try changing it. See the Formatter class for descriptions.
• September 12th, 2010, 06:03 PM
SilentPirate
Re: Area of a triangle (using 2 extra methods) error help