arrays - Filling a vertical matrix Java -

i'm trying fill matrix vertically, 1 row missing. can me ? there code. maybe there easier way fill matrix verically, cant find it.

public static void main(string[]args){     scanner input = new scanner(system.in);     system.out.print("enter value of matrix: ");     int n = input.nextint();      int [][] matrix = new int [n][n];       (int = 1; < matrix.length; i++) {         matrix[0][i] = matrix[0][i -1] + n;      }      for(int = 1; < matrix.length; i++){         (int j = 0; j < matrix.length; j++){         matrix[i][j] = matrix[i -1][j] + 1;          system.out.print(matrix[i][j] + " ");          }             system.out.println();      }              input.close(); } 

output: enter value of matrix: 4 1 5 9 13 2 6 10 14 3 7 11 15

try

 public static void main(string[]args){ scanner input = new scanner(system.in); system.out.print("enter value of matrix: "); int n = input.nextint();  int [][] matrix = new int [n][n];  matrix[0][0]=0;  //you have forgotten first value (int = 1; < matrix.length; i++) {     matrix[0][i] = matrix[0][i -1] + n;     //initializing first line }  for(int = 1; < matrix.length; i++){     (int j = 0; j < matrix.length; j++){     matrix[i][j] = matrix[i -1][j] + 1;     }      // re-loop display time start i=0    for(int = 0; < matrix.length; i++){     (int j = 0; j < matrix.length; j++){      system.out.print(matrix[i][j] + " ");     }          system.out.println();  }          input.close(); }