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Thread: What am i doing wrong?

  1. #1
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    Default What am i doing wrong?

    So, i want the programm to get 2 inputs from the user( car1money car1gas) and outprint them after it gets it. NOTE: i want this to be done with object and method procedures in order to understand the concepts of them( ignore the variables car2money and car2gas cause basically its the same thing). i know this is basic and im not sure if i should post it, but ill make this attemt to get help.

     
    import java.io.*;
    class testCars {
     
    	public static void main(String args[]) throws IOException {
    	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
     
    	//fields
    	double car1money;
    	double car2money;
    	double car1gas;
    	double car2gas;
     
     
    	cars car1 = new Car1object();
    	car1.Car1Method();
     
    }
     
    class cars{
     
     
    	//constructor
    	 Car1object(double car1money,double car1gas){
    		this.car1money= car1money;
    		this.car1gas = car1gas;
    	}
     
    	//method
    	Car1Method(){
    		System.out.println(" Money for the 1st car: ");
    		car1money= br.read();
    		System.out.println(" gas for the 1st car: ");
    		car1gas= br.read();
    		System.out.println("You typed:" + car1money + car1gas);
    		}
     
    	}

    P.S. you can ignore the "throws IOexception" thank you in advance


  2. #2
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    Default Re: What am i doing wrong?

    Is there some reason you're not just using a Scanner( System.in ) to get user input from the keyboard?

  3. #3
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    Default Re: What am i doing wrong?

    Why do you have a constructor for a Carlobject in the class cars?

    Your BufferReader object appears to be only local to the main method. I don't think it can find it inside that other class.

    I see no carlmoney class variable declared inside the cars class.

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    Default Re: What am i doing wrong?

    Is there some reason you're not just using a Scanner( System.in ) to get user input from the keyboard?
    yes, the excercise should be with no Scanner, even though im not sure what that means



    Why do you have a constructor for a Carlobject in the class cars?

    Your BufferReader object appears to be only local to the main method. I don't think it can find it inside that other class.

    I see no carlmoney class variable declared inside the cars class.
    where the constructor should be?

    so the br object has to be public?

    i dont think i understood compeletely what youre saying, but if im getting this, i have all my variables declared in the main class. shouldn't it be that way?

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    Super Moderator Norm's Avatar
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    Default Re: What am i doing wrong?

    have all my variables declared in the main class.
    Where is the class named: main? Did you mean the main() method?
    Variables defined in a method are NOT known outside of that method.
    If you want all the methods in a class to be able to access a variable it should be defined at the class level, outside of any method.
    If you don't understand my answer, don't ignore it, ask a question.

  6. #6
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    Default Re: What am i doing wrong?

    Where is the class named: main? Did you mean the main() method?
    Variables defined in a method are NOT known outside of that method.
    If you want all the methods in a class to be able to access a variable it should be defined at the class level, outside of any method.
    i took all the fields and placed them in the clas cars and now i get 2 errors

    Car1.java:25: error: invalid method declaration; return type required
    Car1object(double car1money,double car1gas){
    ^
    Car1.java:31: error: invalid method declaration; return type required
    Car1Method(){
    ^
    2 errors

    how should i fix this?

  7. #7
    Super Moderator Norm's Avatar
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    Default Re: What am i doing wrong?

    Are those attempts to define a constructor for the classes? The name of the constructor must match EXACTLY the name of the class.

    If those are attempts to define a method in a class, then they must include a return type.

    See the tutorial:
    Defining Methods (The Java™ Tutorials > Learning the Java Language > Classes and Objects)
    Providing Constructors for Your Classes (The Java™ Tutorials > Learning the Java Language > Classes and Objects)
    If you don't understand my answer, don't ignore it, ask a question.

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