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Thread: help creating program for area and perimeter of triangle

  1. #1
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    Default help creating program for area and perimeter of triangle

    import java.lang.Math;
    public class triangle
    {
       double area; double s;
       public double findArea(double sideA, double sideB, double sideC);
    {   
          s= 0.5 *(sideA + sideB + sideC);
          area = Math.sqrt(s*(s-sideA)*(s-sideB)*(s-sideC)); 
          System.out.println("The area of the triangle is " + area);
          return area;
       }     
    }
    import java.util.Scanner
     
       public static void main(String[] args) {
     
          Formula triangle = new Formula();
          double a,b,c;
     
          Scanner inputTriangle = new Scanner(System.in);
          System.out.println("Enter side a of triangle");
          a = inputTriangle.nextDouble();
          System.out.println("Enter side b of triangle");
          b = inputTriangle.nextDouble();
          System.out.println("Enter side c of triangle");
          c = inputTriangle.nextDouble();
          triangle.findArea(a, b, c);
       }      
    }
    I've tried for hours to fix the errors in this simple program for a class I am taking. Help would be appreciated.

    Errors I am getting:

    Triangle.java:23: error: class, interface, or enum expected
    import java.util.Scanner
    ^
    Triangle.java:25: error: class, interface, or enum expected
    public static void main(String[] args) {
    ^
    Triangle.java:28: error: class, interface, or enum expected
    double a,b,c;
    ^
    Triangle.java:30: error: class, interface, or enum expected
    Scanner inputTriangle = new Scanner(System.in);
    ^
    Triangle.java:31: error: class, interface, or enum expected
    System.out.println("Enter side a of triangle");
    ^
    Triangle:32: error: class, interface, or enum expected
    a = inputTriangle.nextDouble();
    ^
    Triangle.java:33: error: class, interface, or enum expected
    System.out.println("Enter side b of triangle");
    ^
    Triangle:34: error: class, interface, or enum expected
    b = inputTriangle.nextDouble();
    ^
    Triangle:35: error: class, interface, or enum expected
    System.out.println("Enter side c of triangle");
    ^
    Triangle.java:36: error: class, interface, or enum expected
    c = inputTriangle.nextDouble();
    ^
    Triangle.java:37: error: class, interface, or enum expected
    triangle.findArea(a, b, c);
    ^
    Triangle.java:38: error: class, interface, or enum expected
    }
    ^
    12 errors
    Last edited by tinker99; September 1st, 2014 at 05:53 PM.


  2. #2
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    Default Re: help creating program for area and perimeter of triangle

    the errors in this simple program
    Please copy the full text of the error message and paste it here. It has important info about the error.

    Please edit your post and wrap your code with code tags:
    [code=java]
    YOUR CODE GOES HERE
    [/code]
    to get highlighting and preserve formatting.
    If you don't understand my answer, don't ignore it, ask a question.

  3. #3
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    Default Re: help creating program for area and perimeter of triangle

    Please follow Java's naming conventions and start your class names with capital letters.

    The class triangle has a close brace, '}', before the method main(), there is an import statement in the middle of your code, and the method findArea() ends with the semicolon at the end of the signature. Indent properly, reorganize your code, remove incorrect semicolons/add needed ones, enclose the main() method in the class, and you should be well on your way. What is Formula?

  4. #4
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    Default Re: help creating program for area and perimeter of triangle

    Quote Originally Posted by GregBrannon View Post
    Please follow Java's naming conventions and start your class names with capital letters.

    The class triangle has a close brace, '}', before the method main(), there is an import statement in the middle of your code, and the method findArea() ends with the semicolon at the end of the signature. Indent properly, reorganize your code, remove incorrect semicolons/add needed ones, enclose the main() method in the class, and you should be well on your way. What is Formula?
    I went ahead and reorganized and simplified, but I am still having some problems. Here is the new code:

    import java.util.Scanner;
     
    public class Triangle {
       public static void main (String[] args) {
           Scanner Console = new Scanner(System.in);
           System.out.print("Please enter the three lengths of your Triangle: ");
           double a = input.nextDouble();
           double b = input.nextDouble();
           double c = input.nextDouble();
           System.out.println("Your three triangle lengths are: " + '\n' + a + '\n' + b + '\n' + c);
           System.out.println("The area of your triangle is: " + getArea(a,b,c));
     
       public static double triangleArea(double a, double b, double c) { 
          double s = (a + b + c)/2.0;
          double x = ((s)*(s-a)*(s-b)*(s-c));
          double area = Math.sqrt(x);
          return area;
       }      
    }
    and here are the errors:

    Triangle.java:23: error: illegal start of expression
    public static double triangleArea(double a, double b, double c) {
    ^
    Triangle.java:23: error: illegal start of expression
    public static double triangleArea(double a, double b, double c) {
    ^
    Triangle.java:23: error: ';' expected
    public static double triangleArea(double a, double b, double c) {
    ^
    Triangle.java:23: error: '.class' expected
    public static double triangleArea(double a, double b, double c) {
    ^
    Triangle.java:23: error: ';' expected
    public static double triangleArea(double a, double b, double c) {
    ^
    Triangle.java:23: error: <identifier> expected
    public static double triangleArea(double a, double b, double c) {
    ^
    Triangle.java:23: error: not a statement
    public static double triangleArea(double a, double b, double c) {
    ^
    Triangle.java:23: error: ';' expected
    public static double triangleArea(double a, double b, double c) {
    ^
    Triangle.java:29: error: reached end of file while parsing
    }
    ^

  5. #5
    Super Moderator Norm's Avatar
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    Default Re: help creating program for area and perimeter of triangle

    It looks like there is a problem with the pairing of the {}s
    Make sure the code for every method is enclosed within {}s.
    One method can NOT be inside of another.

    It might help to see the pairing if the ending } for a method has a label;
        } //  end main()

    Also the ending/pairing } should be in the same column as the first character on the line with the { that goes with it:
         if(x > 1 ) {
            //  something
         }  //  this is under the i in if
    If you don't understand my answer, don't ignore it, ask a question.

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    Default Re: help creating program for area and perimeter of triangle

    Also posted at: Area Of Triangle Java Program Help? - Java | Dream.In.Code
    If you don't understand my answer, don't ignore it, ask a question.

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