Thread: Begineer mistakes, need help (very basic)

I started java about 3 week ago, I have no experience in computer science at all, except some 3D artist ones
I work very hard but I can't understand anything about the structure, syntax and all.
I am overwhelmed by my work and I find it hard to keep up with the group.

This is my first java code, it's about calculating a car average speed (km per hour) and consumption per minute

Forgive my english I am not a native speaker at all.

Originally Posted by skeletonbutler

This is my first java code

...Where

import java.text.DecimalFormat;
 
import javax.swing.JOptionPane;
 
public class Cars {
	public double converthourminutes(int byMinute) {
		double nbHours = (double) byMinute / 60;
		return nbHours;
	}
 
//this convert minutes into hours
//I guess it works
 
 
	public static int askInteger(String byMessage) {
		int integer= 0;
		integer = Integer.parseInt(JOptionPane.showInputDialog(null, byMessage,
				"Saisie", JOptionPane.QUESTION_MESSAGE));
		return integer;
	}
 
 
 
 
	public double calculateaverageconsumption(int byDistance, int byConsommation) {
		float calculateaverageconsumption = (float) byDistance / byConsommation;
 
		return averageconsumption;
	}
 
	public static void main(String[] args) {
		int distance, consumption, duration, averageconsumption;
		double nbHours = 0f, averagespeed = 0f;
	}
 
	public float calculateaveragespeed(int byDistance, float byDuration) {
 
		float averagespeed = byDistance / byDuration;
 
		return averagespeed;
 
		consumption = Cars.askInteger(" fuel consumption :");
		duration = Cars.askInteger(" time of the travel in minute");
		distance = Cars.askInteger("kilometers travelled");
 
		nbHours = Cars.converthourminutes(duration);
 
		averagespeed = Cars.calculateaveragespeed(distance, nbHours);
 
		averageconsumption = Cars.calculateaverageconsumption(distance,
				consumption);
 
		JOptionPane.showMessageDialog(null,
				" Your speed is : " + speed.format(averagespeed)
						+ " km per hour" + "Your average consumption is: "
						+ averageconsumption + " kilometre per liter",
				JOptionPane.INFORMATION_MESSAGE);
 
	}
}

sorry I thought I had it on attachment

Where should I put my main function? Eclipse doesn't find it anywhere even though I added public static void main(String[] args) {

Originally Posted by skeletonbutler

Eclipse doesn't find it anywhere even though I added public static void main(String[] args) {

What do you mean by this? If there is an error message, copy-paste it here. Are you trying to export or run within the ide?

public double calculateaverageconsumption(int byDistance, int byConsommation) {
		float calculateaverageconsumption = (float) byDistance / byConsommation;
 
		return averageconsumption;
	}

This is going to give you trouble. You return a non-existent variable. You called the var "calculateaverageconsumption." Then you return "averageconsumption."

-summit45

After reading post #6...

public float calculateaveragespeed(int byDistance, float byDuration) {
 
		float averagespeed = byDistance / byDuration;
 
		return averagespeed;//Method returns here
 /*-------------- All code below this line can not be reached --------------*/
		consumption = Cars.askInteger(" fuel consumption :");
		duration = Cars.askInteger(" time of the travel in minute");
		distance = Cars.askInteger("kilometers travelled");
 
		nbHours = Cars.converthourminutes(duration);
 
		averagespeed = Cars.calculateaveragespeed(distance, nbHours);
 
		averageconsumption = Cars.calculateaverageconsumption(distance,
				consumption);
 
		JOptionPane.showMessageDialog(null,
				" Your speed is : " + speed.format(averagespeed)
						+ " km per hour" + "Your average consumption is: "
						+ averageconsumption + " kilometre per liter",
				JOptionPane.INFORMATION_MESSAGE);
 
	}