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Thread: Begineer mistakes, need help (very basic)

  1. #1
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    Default 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.


  2. #2
    Super Moderator jps's Avatar
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    Default Re: Begineer mistakes, need help (very basic)

    Quote Originally Posted by skeletonbutler View Post
    This is my first java code
    ...Where

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    Default Re: Begineer mistakes, need help (very basic)

    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) {

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    Senior Member PhHein's Avatar
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    Default Re: Begineer mistakes, need help (very basic)

    Ok, now repost using code tags. And asking questions might help too.

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    Super Moderator jps's Avatar
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    Default Re: Begineer mistakes, need help (very basic)

    Quote Originally Posted by skeletonbutler View Post
    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?

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    Default Re: Begineer mistakes, need help (very basic)

    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

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    Default Re: Begineer mistakes, need help (very basic)

    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);
     
    	}

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