I'm writing a program that calculates the hypotenuse of a triangle, and I'm supposed to call up a method into the main.
Is it better to have them in 2 separate files, or to have the method I'm calling up in the program I'm running?
In the program, I keep getting error messages about the last line of code, with the JOptionPane output.
What am I getting wrong?
import javax.swing.JOptionPane;
import java.util.Scanner;
public class A2
{
public static double Hypo(double a,double b,double c);
double a,b,c;
{
hyp=((a*a)+(b*b));
c=Math.sqrt(hyp);
}
int x,y;
double c;
String text1=JOptionPane.showInputDialog("How long is side A? ");
int x=Integer.parseInt(text1);
String text2=JOptionPanes.howInputDialog("How long is side B? ");
int y=Integer.parseInt(text2);
double c=A2.Hypo(x,y);
JOptionPane.showMessageDialog(null, "The hypotenuse of the triangle is " +c);
}
This code has so many problems it's hard to know where to begin.
Here's some advice:
Start with this. It runs and gives correct results:
import javax.swing.*;
/**
* A2
* @author Michael
* @link https://stackoverflow.com/questions/30965862/calling-method-to-a-main-in-java
* @since 6/21/2015 11:00 AM
*/
public class SimpleMathDemo {
public static double hypotenuse(double a,double b) {
return Math.sqrt(a*a+b*b);
}
public static void main(String[] args) {
String text1= JOptionPane.showInputDialog("How long is side A? ");
int x=Integer.parseInt(text1);
String text2=JOptionPane.showInputDialog("How long is side B? ");
int y=Integer.parseInt(text2);
double c= SimpleMathDemo.hypotenuse(x,y);
JOptionPane.showMessageDialog(null, "The hypotenuse of the triangle is " +c);
}
}
Code analysis
public class A2 {
//Missing method body no return values ..Is this an abstact function?/
public static double Hypo(double a, double b, double c);
double a, b, c;
//Whats this part doing hanging in the middle??
{
//where is the variable declaration of hyp
hyp = ((a * a) + (b * b));
c = Math.sqrt(hyp);
}
int x, y;
//variable c is already declared
double c;
String text1 = JOptionPane.showInputDialog("How long is side A? ");
//variable x is already declared
int x = Integer.parseInt(text1);
//JOptionPane not JOptionPanes
String text2 = JOptionPanes.howInputDialog("How long is side B? ");
//variable y is already declared
int y = Integer.parseInt(text2);
//variable c is already declared and Hypo function has three arguements in the declaration
double c = A2.Hypo(x, y);
//wont work because the whole code is buggy
JOptionPane.showMessageDialog (null, "The hypotenuse of the triangle is " +c);
}
}
To elaborate more:
import javax.swing.JOptionPane;
public class A2 {
public static double Hypo(int a, int b) {
double hyp=((a*a)+(b*b));
double c=Math.sqrt(hyp);
return c;
}
public static void main(String[] args) {
int x, y;
double c;
String text1=JOptionPane.showInputDialog("How long is side A? ");
x=Integer.parseInt(text1);
String text2=JOptionPane.showInputDialog("How long is side B? ");
y=Integer.parseInt(text2);
JOptionPane.showMessageDialog(null, "The hypotenuse of the triangle is " + Hypo(x,y));
}
}
You need to choose a correct return type, whether it be void, int, double, etc, and each method with a return type should return a value with the set type.
You also always need at least one main method in a program. There can be multiple in different classes.
You will need to use a more specific variable names, and follow oracle convention for brackets {}.
DO not declare a variable twice as in:
int x, y;
int x = 1; // WRONG
x = 1; // Correct
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