using length() on an array

Question

need to create a int length() method where the array is outside of the method . Was thinking of doing a for loop for (int i = 0; i < array.length; i++)...but im not sure help please. on API it looks easy but the array is not in the method itself so idk how to do it.

public class MyString
{

    private char[] array;
    private int size;
    private int max;

    public MyString()
    {
        array = new char[25];
        max = 25;
    }
    public void setString(String newString)
    {
     if(newString.length() > 25)
     {
         System.out.println("/nEnter a number equal or less than 25 " );

     }
     else
     {
      for(int i=0; i < newString.length(); i++)
      {
        array[i] = newString.charAt(i);
      }
     }
    }


    public String toString()
    {
        return new String(array);
    }

    public char charAt(int index)
    {
        return array[index];
    }

    public boolean contains(char ch)
    {
        for(char c: array)
        {
            if(c == ch) return true;
        }
        return false;
     }
     public int indexOf( char ch )
     {
        for (int i = 0; i < array.length; i++)
        {
           if (array[i] == ch)
           {
               return i;   // Character found, return current index
           }
         }
            return -1;    // Character not found. Return -1
      }
      public int length()
      {

is this homework? If yes, please add a tag for it homework — Fahim Parkar
– Fahim Parkar, Commented Nov 13, 2012 at 6:58
@Andreas : Ohh... thanks for sharing that. I know un-aware. Also I don't understand, when TAG is deprecated, why it still exists in SO? — Fahim Parkar
– Fahim Parkar, Commented Nov 13, 2012 at 7:09

Grisha Weintraub · Accepted Answer · 2012-11-13 07:08:41Z

1

In your examplearray.length always will return 25. If you want the length of array with values, use :

  public int length(){
       int i = 0;
       for (char c : array) {               
           if (c == '\u0000')
               return i;  
           i++;         
       }
       return array.length;
  }

answered Nov 13, 2012 at 7:08

Grisha Weintraub

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Comments

Andreas Fester · Accepted Answer · 2012-11-13 07:17:39Z

0

I am not sure if I get your question completely right, but

public int length() {
   return array.length;
}

should do it. An array in java has a length member which contains the array length.

Note that this returns the Array length which will always be 25 in the code from your question.

If you want the String length, either use the approach from @Grisha, or use the size member which is already in your code but not used yet:

public MyString() {
   array = new char[25];
   max = 25;

   size = 0;
}

public void setString(String newString) {
   if(newString.length() > 25) {
      System.out.println("/nEnter a number equal or less than 25 " );
   } else {
      size = newString.length();

      for(int i = 0; i < size; i++) {
          array[i] = newString.charAt(i);
      }
   }
}

public int length() {
   return size;
}

This would avoid a loop with linear complexity (length() would be O(1) and not O(n)).

edited Nov 13, 2012 at 7:17

answered Nov 13, 2012 at 6:58

Andreas Fester

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9 Comments

javip Over a year ago

wow is that it? i thought it would be more work. but pretty much just need to get the length of the array

Fahim Parkar Over a year ago

need to create a int length(). I think OP want to create length method and not use the default one.

Fahim Parkar Over a year ago

Ohh.. OP wanted what you said.

Andreas Fester Over a year ago

@codeMaker Yes, I was thinking that way also, but than the answer would have been return 25. By returning array.length, you still have a single position in the code where you can adjust the maximum length.

Andreas Fester Over a year ago

@codeMaker Ahhh, got it - OP wants to return the String length, not the array length.

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