How to prevent number duplication in Java.

Question

How do i prevent number duplication in this program. Basically so that i don't have to enter the same number again
here's the code:
import java.awt.*;
import hsa.Console;
public class BubbleSort_Strings
    static Console c;           // The output console
    public static void main (String[] args)
        c = new Console ();
        c.println ("\t\t\tIPOD Downloads\n\n");
        c.print ("Enter the number of songs: ");
        int max = c.readInt ();
        c.println ();
        String song[] = new String [max];
        String tempSong;
        for (int i = 0 ; i <= max - 1 ; i = i + 1)
            c.print ("Enter the name of song " + (i + 1) + ": ");
            song = c.readLine ();
c.println ();
} //end for i
//sort the song names in the array alphabetically
for (int x = 0 ; x < max - 1 ; x++)
for (int y = x + 1 ; y < max ; y++)
if (song [x].compareTo (song [y]) > 0)
tempSong = song [x];
song [x] = song [y];
song [y] = tempSong;
} //end if
} //end for y
} //end for x
c.println ("Your songs have now been sorted:");
c.println ();
for (int z = 0 ; z <= max - 1 ; z = z + 1)
c.println (song [z]);
} //end for z
} // main method
} // BubbleSort_Strings class

Answer 1

here how about this:
// The "BubbleSort_Numbers" class.
import java.awt.*;
import hsa.Console;
public class BubbleSort_Numbers
    static Console c;           // The output console
    public static void main (String[] args)
        c = new Console ();
        c.print ("Enter the number of items: ");
        int max = c.readInt();
        int item[] = new int [max];
        int temp;
        for (int i = 0 ; i <= max - 1 ; i = i + 1)
            c.print ("Enter a number for the array: ");
            item = c.readInt ();
} //end for i
for (int x = 0 ; x < max - 1 ; x++)
for (int y = x + 1 ; y < max ; y++)
if (item [x] < item [y])
temp = item [x];
item [x] = item [y];
item [y] = temp;
} //end if
} //end for y
} //end for x
c.println ("The numbers have been sorted.");
for (int z = 0 ; z <= max - 1 ; z = z + 1)
c.println (item [z]);
} //end for z
} // main method
} // BubbleSort_Numbers class