C # Operator

1. Conditional operators (? :), Also known as the ternary (object) operator, is a simplified form of the if... else structure and can be nested for use. [Csharp] int x = 1; string s = x + ""; s + = (x = 1? "Man": "men"); Console. writeLine (s); // output 1man 2, checked, and unchecked [csharp] byte B = 255; {B ++;} Console. writeLine (B. toString (); // the output value is 0, but the byte value can only contain 0-values. Therefore, B overflows after ++. Therefore, if a code block is marked as checked, the CLR performs an overflow check. If a code block overflows, an OverflowException exception is thrown. [Csharp] byte B = 255; checked {B ++;} Console. writeLine (B. toString (); // throw an OverflowException exception. overflow caused by arithmetic operations. To disable the overflow check, mark it as unchecked: [csharp] byte B = 255; unchecked {B ++;} Console. writeLine (B. toString (); // outputs 0 without throwing an exception. 3. The is operator can check whether the object is compatible with a specific type. "Compatible" indicates that the object belongs to this type or is derived from this type. [Csharp] string I = "hello I... "; if (I is object) {Console. writeLine ("I is an object... "); // executed this sentence} 4. The as operator is used to execute the explicit type conversion of the reference type (string is the reference type ). If the type to be converted is compatible with the specified type, the conversion is successful. If the type is incompatible, The as operator returns Null. [Csharp] string I = "hello I... "; if (I is object) {object obj = I as object; // Console for explicit type conversion. writeLine (obj is string? "Obj is string... ":" obj is not string... "); // output obj is string ...} 5. the sizeof operator can determine the length (in bytes) required for the stack Value Type: [csharp] int byteSize = sizeof (byte ); // output 1 int charSize = sizeof (char); // output 2 int uintSize = sizeof (uint); // output 4 int intSize = sizeof (int ); // output 4 6. the typeof operator is often used together with the GetType () method to reflect the attributes and methods of the class. [Csharp] Type intType = typeof (int); System. reflection. methodInfo [] methodInfo = intType. getMethods (); methodInfo. toList (). forEach (x => Console. writeLine (x. name); // reflect the method Name of the int type. 7. null type and operator. if one or both of the operands are null, the result is null, for example: [csharp] int? A = null; int? B = a + 4; // B = null int? C = a * 5; // c = null, but when the comparison can be null, if one of the operands is null, the comparison result is false. However, because a condition is false, the opposite of the condition is true. For example, [csharp] int? A = null; int? B =-5; if (a> = B) Console. writeLine ("a> = B"); else Console. writeLine ("a <B"); // This sentence is output. 8. null merge operators such as: [csharp] int? A = null; // Add a question mark to assign a null Int B to the int type; B = ?? 1; [csharp] Console. WriteLine (B); // output 1 a = 3; B = ?? 10; Console. WriteLine (B); // output 10