!= Operator (C# Reference)
The inequality operator (!=) returns false if its operands are equal, true otherwise. Inequality operators are predefined for all types, including string and object. User-defined types can overload the != operator.
For predefined value types, the inequality operator (!=) returns true if the values of its operands are different, false otherwise. For reference types other than string, != returns true if its two operands refer to different objects. For the string type, != compares the values of the strings.
User-defined value types can overload the != operator (see operator). So can user-defined reference types, although by default != behaves as described above for both predefined and user-defined reference types. If != is overloaded, == must also be overloaded. Operations on integral types are generally allowed on enumeration.
class InequalityTest { static void Main() { // Numeric inequality: Console.WriteLine((2 + 2) != 4); // Reference equality: two objects, same boxed value object s = 1; object t = 1; Console.WriteLine(s != t); // String equality: same string value, same string objects string a = "hello"; string b = "hello"; // compare string values Console.WriteLine(a != b); // compare string references Console.WriteLine((object)a != (object)b); } } /* Output: False True False False */
