Trouble with Method undefined for a type Java

user_11924085 0
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I'm new to Java programming and having a hard time understanding the use of methods and how to use them in the code. I know this is really basic things and I'm trying, it's just hard to grasp at first. So tl;dr I don't quite understand this error or how to fix it. 

public class TriangleInfo {

    public static void main(String args[]) {
        Triangle versuch = createTriangle();
    }

    public static createTriangle() {
        double side1 = 90;
        double side2 = 80;
        double hypotenuse = getHypotenuse();
        Triangle thisTriangle = new Triangle(side1, side2, hypotenuse);     
        return thisTriangle;
    }

    public static double getHypotenuse() {
        return Math.sqrt(Math.pow(side1, 2) + Math.pow(side2, 2));
    }
}

The error I'm getting is:

The method createTriangle() is undefined for the type TriangleInfo

I also have this written in another file: 

public class Triangle {
    double side1;
    double side2;
    double hypotenuse;

    // Konstrukturen
    public Triangle(double sideOne, double sideTwo, double hypotenuse) {
        this.sideOne = sideOne;
        this.sideTwo = sideTwo;
        this.hypotenuse = hypotenuse;
    }
}

Could someone please help me understand this error and how to correct it? Thank you!

java
2 Answers

The error is that your method createTriangle() doesn't have a return type. Since you are returning a Triangle, you need to add that.

public static Triangle createTriangle() {

And continue with your normal code.

Also, a good catch from @JO3-W3B-D3V, the side1 and side2 are not globally accessible in the class, so you need to do:

public static double getHypotenuse(double side1, double side2) {
    return Math.sqrt(Math.pow(side1, 2) + Math.pow(side2, 2));
}

So, your complete createTriangle() function becomes:

public static Triangle createTriangle(){
    double side1 = 90;
    double side2 = 80;
    double hypotenuse = getHypotenuse(side1, side2);
    Triangle thisTriangle = new Triangle(side1, side2, hypotenuse);  
    return thisTriangle;   
}
user_100456600

Okay, first of all, looking at the code you've provided, the method createTriangle does not have a return type specified, all you need to do here is refactor it like so:

public static Triangle createTriangle() { // Body of the method...

Then there's the matter of the getHypotenuse method, since it has no reference to the values side1 or side2, you need to either alter it such that the these variables are properties within the class, or you can update the method & the caller, like so:

Caller

double hypotenuse = getHypotenuse(side1, side2);

Method

public static double getHypotenuse(double side1, double side2) { // Body of the method...

Finally, in the Triangle class, you have the property names stated as side, but in the constructor of the Triangle class, you try to assign this.sideOne, it should either be side1 in the constructor, or you should change the name(s) of the class properties.

Summary

To be fair, I appreciate that you're a beginner & to be fair, you weren't too far from having a working implementation.

Complete Solution

import java.lang.Math;

public class TriangleInfo {

    public static void main(String args[]) {
        Triangle versuch = createTriangle();
    }

    public static Triangle createTriangle() {
        double side1 = 90;
        double side2 = 80;

        double hypotenuse = getHypotenuse(side1, side2);
        Triangle thisTriangle = new Triangle(side1, side2, hypotenuse);
        return thisTriangle;
    }

    public static double getHypotenuse(double side1, double side2) {
        return Math.sqrt(Math.pow(side1, 2) + Math.pow(side2, 2));
    }
}

class Triangle {
    double side1;
    double side2;
    double hypotenuse;

    // Konstrukturen
    public Triangle(double sideOne, double sideTwo, double hypotenuse) {
        this.side1 = sideOne;
        this.side2 = sideTwo;
        this.hypotenuse = hypotenuse;
    }
}
user_81880600
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