Question

I'm writing this class called CharArrayProject_3 that removes repeating elements from an array of chars. However, when I run the driver class, it just outputs two sets of dashed lines. What am I getting wrong? Is it the deleteRepeats() method?:

public class CharArrayProject_3
{
private char[] array;
privateint length;
privateintnumberOfRepeats;

public CharArrayProject_3( char[] arr )
{
length = arr.length;
array = new char[ length ];
numberOfRepeats = 0;
for( int k = 0; k < arr.length; k++ )
{ array[k] = arr[k]; }
}

public void deleteRepeats()
{
int j = 0;//for next element
for (inti=0; i < length-1; i++){
if (array[i] == array[i+1]){
array[j++] = array[i];
numberOfRepeats++;
}
}
array[j++] = array[length-1];
}
}

public String toString()
{
String result;
for (char value : array)
{
result += value;
}
String result = "\nNumber of Repeats: " + numberOfRepeats;
return result;
}
}

public class CharArrayProject_3_Driver
{
public static void main( String args[] )
{
char a[] = { 'h','o','l','l','y',
'c','l','e','m','e','n','c','e' };
CharArrayProject_3 hello = new CharArrayProject_3( a );
hello.toString();
hello.deleteRepeats();
System.out.println();
hello.toString();
System.out.print( "\n-----------------------------\n" +
"-----------------------------\n");
char b[] = { 'a','b','c','b','b',
'c','a','d','a','d','c' };
hello = new CharArrayProject_3( b );
hello.toString();
hello.deleteRepeats();
System.out.println();
hello.toString();
}
}

Answer 1

the only modification I made to get it to work was to add the hello.toString() line into a print statement. The toString function returns a string but does not print the string itself.

only you know if the code does the right thing.

I've boldened the modifications

please drop a comment if there's a problem

//--------------------------------------------

public class CharArrayProject_3_Driver {

    public static void main(String args[]) {

        char a[] = { 'h', 'o', 'l', 'l', 'y', 'c', 'l', 'e', 'm', 'e', 'n', 'c', 'e' };

        CharArrayProject_3 hello = new CharArrayProject_3(a);

        System.out.println(hello.toString());

        

        hello.deleteRepeats();

        System.out.println(hello.toString());

        

        System.out.print("\n-----------------------------\n" + "-----------------------------\n");

        char b[] = { 'a', 'b', 'c', 'b', 'b', 'c', 'a', 'd', 'a', 'd', 'c' };

        hello = new CharArrayProject_3(b);

        System.out.println(hello.toString());

        hello.deleteRepeats();

        System.out.println();

        System.out.println(hello.toString());

    }

}

//-----OUTPUT------

Number of Repeats: 0

Number of Repeats: 1

-----------------------------
-----------------------------

Number of Repeats: 0

Number of Repeats: 1