1structtest{2inta;3};4intmain(){5structtest t;6printf("%d\n",t.a);7} 若test的默认构造函数产生,并导致a被初始化为0,那么C++中就将输出0。但C中没有构造函数这一概念,所以就将输出任意值。早期C++是目地之一为了很好的兼容C代码,所以C++编译器为了更好的兼容C,就选择了这种看似很不可思议的方法。
A constructor in C# is called when a class or struct is created. Use constructors to set defaults, limit instantiation, and write flexible, easy-to-read code.
Instance fields (other thanfixedfields) must be definitely assigned in struct instance constructors that do not have athis()initializer (see§15.4.9). C# structS0// ok{intx;objecty; }structS1// error: 'struct' with field initializers must include an explicitly declared constructor{intx =1;...
Alternatively, somestructtypes (including all built-in numeric types) can be initialized or assigned and then used as in the following example: C# inta =44;// Initialize the value type...intb; b =33;// Or assign it before using it.Console.WriteLine("{0}, {1}", a, b); ...
Learn how and when to declare primary constructors in your class and struct types. Primary constructors provide concise syntax to declare constructor parameters available anywhere in your type.
A class or struct can only have one static constructor. Static constructors cannot be inherited or overloaded. A static constructor cannot be called directly and is only meant to be called by the common language runtime (CLR). It is invoked automatically. The user has no control on when...
Structs cannot contain an explicit default constructor because one is provided automatically by the compiler. This constructor initializes each field in the struct to the default values. Instance Constructors in C# Default Constructor Parameterized Constructor ...
Primary constructors are a new feature in C# 12 that allows you to declare and use constructor parameters anywhere in the body of a class or a struct. They are a concise way to initialize properties or fields, call base constructors, or reference the parameters in other members of the ...
Another crucial thing is the fact thatall constructors in a class should call the primary one using thethiskeyword. Calling the primary constructor is a requirement to ensure that all essential data is available for the creation of a class or struct. Failure to do so will result in errors ...
Here are some basic working principle of static constructor in C# which are as follows: When a class or an object of the class is created as a struct, constructors are called upon to create the data members associated with the class. These constructors have the same name as the class. ...