public static void main ( String [ ] args ) {
  int matrix [ ] [ ] = new int [ 5 ] [ 5 ] , row_index , column_index , x = 0 , size = 5 ;
  for ( row_index = 0 ;
  row_index < size ;
  row_index ++ ) {
    for ( column_index = 0 ;
    column_index < size ;
    column_index ++ ) {
      matrix [ row_index ] [ column_index ] = ++ x ;
    }
  }
  System . out . printf ( "The matrix is\n" ) ;
  for ( row_index = 0 ;
  row_index < size ;
  row_index ++ ) {
    for ( column_index = 0 ;
    column_index < size ;
    column_index ++ ) {
      System . out . printf ( "%d\t" , matrix [ row_index ] [ column_index ] ) ;
    }
    System . out . printf ( "\n" ) ;
  }
  System . out . printf ( "\nMain diagonal elements are:\n" ) ;
  for ( row_index = 0 ;
  row_index < size ;
  row_index ++ ) {
    for ( column_index = 0 ;
    column_index < size ;
    column_index ++ ) {
      if ( row_index == column_index ) {
        System . out . printf ( "%d, " , matrix [ row_index ] [ column_index ] ) ;
      }
    }
  }
}

public static void main ( String [ ] args ) { int matrix [ ] [ ] = new int [ 5 ] [ 5 ] , row_index , column_index , x = 0 , size = 5 ; for ( row_index = 0 ; row_index < size ; row_index ++ ) { for ( column_index = 0 ; column_index < size ; column_index ++ ) { matrix [ row_index ] [ column_index ] = ++ x ; } } System . out . printf ( " The ▁ matrix ▁ is \n " ) ; for ( row_index = 0 ; row_index < size ; row_index ++ ) { for ( column_index = 0 ; column_index < size ; column_index ++ ) { System . out . printf ( " % d\t " , matrix [ row_index ] [ column_index ] ) ; } System . out . printf ( " \n " ) ; } System . out . printf ( " \n Main ▁ diagonal ▁ elements ▁ are : \n " ) ; for ( row_index = 0 ; row_index < size ; row_index ++ ) { for ( column_index = 0 ; column_index < size ; column_index ++ ) { if ( row_index == column_index ) { System . out . printf ( " % d , ▁ " , matrix [ row_index ] [ column_index ] ) ; } } } }
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