java - Print out a string of characters from a 2D array into a certain number of rows -

i'm trying make keypad in java takes letters input user, desired number of characters per row. should print characters in desired number of rows, if "abcdefgh" input , desired row number 4 should print:

abcd   efgh   

but i'm stuck on how work.

public class keypad {  char [][] letters;   public keypad(string chars, int rowlength) {     int counter = 0;      (int = 0; i<chars.length(); i++){         counter++;      }     letters = new char[rowlength][counter/rowlength];   }  public string tostring() {     string s = " ";       (int row=0; row<letters.length; row=row+1) { // on rows         (int col=0; col<letters[row].length; col=col+1) {               s = s + letters[row][col];         }         s = s + "\n";     }     return "the keypad is" + s;  } 

the logic of tostring() method looks fine, didn't populate letters array in constructor. need add in constructor:

    public keypad(string chars, int rowlength) {         // don't need count length loop         int nrow = chars.length()/rowlength;         if(chars.length()%rowlength!=0) nrow++;         letters = new char[nrow][rowlength];          for(int = 0, n = 0 ; < letters.length ; i++) {             for(int j = 0 ; n < chars.length() && j < letters[i].length ; j++, n++) {                 letters[i][j] = chars.charat(n);             }         }     }