Conditional Operator / Ternary Operator :   condition ? true_expression : false_expression;  bool x = condition ? true : false;   eg :  string   result  = (percentage  >= 36)  ?  "pass"  :  "fail" ;    --------------------------------------------------------  NullCoalesce (??)   int totalMarks = marks ?? 0 ;   The  ??  operator is called the null-coalescing operator. It returns the left-hand operand if the operand is not null; otherwise it returns the right hand operand. eg:     int ? x = null ;  int  y = x ?? -1;   int? is a shorthand for Nullable, which itself is shorthand of Nullable.  eg Nullable a = null; A nullable type can represent the correct range of values for its underlying  value type, plus a additional null value.    --------------------------------------------------------