static boolean isDiagonalMatrix ( int mat [ ] [ ] ) {
  for ( int i = 0 ;
  i < N ;
  i ++ ) for ( int j = 0 ;
  j < N ;
  j ++ ) if ( ( i != j ) && ( mat [ i ] [ j ] != 0 ) ) return false ;
  return true ;
}

static boolean isDiagonalMatrix ( int mat [ ] [ ] ) { for ( int i = 0 ; i < N ; i ++ ) for ( int j = 0 ; j < N ; j ++ ) if ( ( i != j ) && ( mat [ i ] [ j ] != 0 ) ) return false ; return true ; }
(method_declaration (modifiers) type: (boolean_type) name: (identifier) parameters: (formal_parameters (formal_parameter type: (integral_type) name: (identifier) dimensions: (dimensions))) body: (block (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) condition: (binary_expression left: (identifier) right: (identifier)) update: (update_expression (identifier)) body: (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) condition: (binary_expression left: (identifier) right: (identifier)) update: (update_expression (identifier)) body: (if_statement condition: (parenthesized_expression (binary_expression left: (parenthesized_expression (binary_expression left: (identifier) right: (identifier))) right: (parenthesized_expression (binary_expression left: (array_access array: (array_access array: (identifier) index: (identifier)) index: (identifier)) right: (decimal_integer_literal))))) consequence: (return_statement (false))))) (return_statement (true))))