Mark Webb

[Java] On Cannot Ref from Static Content

2007-11-09T15:17:32-08:00

A way to make the class work by altering the getCount method without changing the constructor.

[Java] On Cannot Ref from Static Content

2007-11-09T15:00:57-08:00

Is there a way to change it without changing the constructor?

[Java] Cannot Ref from Static Content

2007-11-09T14:45:45-08:00

If anyone can tell me what Ive done wrong here that would be great.

Space.java:69: non-static method getCount() cannot be referenced from a static context

public class Space {
    private int count;
    private String varStr;
    private int varNum;

     
       private Space(String varStr) {
         varStr = varStr;
      }

         private Space(String varStr, int varNum) {                                                                                                        
         varNum = varNum;
      }
     
       public int getCount() { 
          return count;
      }

       public String getVarStr() {                                                                                                                
         return varStr;
      }

       public void setVarStr(String varStr) {
          varStr = varStr;
      }

       public int getVarNum() {                                                                                                          
         return varNum;
      }
  
       public void setVarNum(int varNum) {
          varNum = varNum;
      }


      /* toString */
       public String toString()
      {
         String output = "varNum is 1 str is A string ";
         return output;

      }

    /* equals method */
      public boolean equals (Object o){
         boolean result = false;
          
	  Space other;
            if (o instanceof Space){
            other = (Space)o;

            result = getVarNum() == other.getVarNum();
           }


         return result;
      }


    /*
       DRIVER
     */
    public static void main(String[] args) {
        System.out.println("Space begin\n");

        /* calls the class method */
         System.out.println("\tgetCount= " +Space.getCount());

        /* calls constructor */
          Space q1 = new Space("A string");
          Space q2 = new Space("A string", 3);

        /* calls the class method again */
         System.out.println("\tgetCount= " +Space.getCount());

        /* calls toString method  */
         System.out.println("\ttoString= " +q1);

        /* calls your mutator method */
         q1.setVarStr("Diff");
         q2.setVarNum(5);

        /* calls your accessor method */
         System.out.println("\tget= " +q1.getVarStr());
         System.out.println("\tget= " +q2.getVarNum());


        /* calls your equals method */
         System.out.println("\tequals= " +q1.equals(q1));
         System.out.println("\tequals= " +q1.equals(q2));

        System.out.println("\nSpace end\n");
    }
}

[Java] On Help with new methods

2007-11-06T12:26:53-08:00

Many thanks

[Java] Help with new methods

2007-11-06T07:28:03-08:00

Having some trouble with the methods, I've included some comments so you can see what I tried or intented to achieve here.

public class SchoolRoom {
    private String [] students;
    
    public SchoolRoom(String [] students) {
        this.students = students;
    }

    // Returns the number of students in this SchoolRoom.                                       
    public int enrolment() {
       return students; 
    } 
 
    /**
     * Returns the index of the specified student in this SchoolRoom.
     * If the student appears more than once, only the index
     * of the first one (counting from the left) is returned. If the
     * student is not found in the array, -1 is returned.
     * if it is found. Returns -1 if the student is not in the array.
     */
     public int indexOf(String target) {
       

    }

    /**
     * Compares this SchoolRoom object to the object passed
     * to the method. If that object is also an instance of
     * SchoolRoom, has the same enrolment (number of students), and 
     * every Student's name in that object is the same as the name 
     * of every Student in the same array position in this
     * SchoolRoom, then the objects are equal.
     */
    public boolean equals(Object otherString) {

        SchoolRoom tmpObj = (SchoolRoom) o;

        if (!(o instanceof SchoolRoom))
            return false;

        //return (;

    }

    /**
     * Returns a new SchoolRoom which has the same students
     * as this SchoolRoom, but in reverse order. 
     */
    public SchoolRoom reverse() {

 
    }
 
    /**
     * Returns a new SchoolRoom which has all-capitals names corresponding
     * to the students in this Schoolroom. 
     */
     public SchoolRoom capitalize() {
        String SchoolRoom;

        System.out.println(SchoolRoom.toUpperCase()); 
     }
}

[Java] On Errors With Exception

2007-11-05T08:38:20-08:00

I see, I didnt instantiate the array correctly. Thank you.

[Java] Errors With Exception

2007-11-05T07:03:08-08:00

It compiles, although when I try to run it, I get an exception.

public class Parks {
    private String[] parkingBays;
    private int numCars;

    public Parks(int capacity) {
        parkingBays = new String[numCars];

        for (int i = 0; i <= parkingBays.length; i++) {
            parkingBays[i] = "Empty";
        }
    }
    public boolean park(String car) {
        
        if (numCars > parkingBays.length){
            parkingBays[++numCars] = car;
        }
        else {
            return false;
        }
        return true;
    }


    /**
     * For Testing
     */
    public static void main(String [] args) {
        Parks p = new Parks(20);
        boolean spaces = true;
        while (spaces) {
            spaces = p.park("car1");
            spaces = p.park("car2");
        }
        for (String car : p.parkingBays)
            System.out.println(car);
    }
}