C# Language Structs Declaring a struct
Example
public struct Vector
{
public int X;
public int Y;
public int Z;
}
public struct Point
{
public decimal x, y;
public Point(decimal pointX, decimal pointY)
{
x = pointX;
y = pointY;
}
}
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structinstance fields can be set via a parametrized constructor or individually afterstructconstruction. -
Private members can only be initialized by the constructor.
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structdefines a sealed type that implicitly inherits from System.ValueType. -
Structs cannot inherit from any other type, but they can implement interfaces.
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Structs are copied on assignment, meaning all data is copied to the new instance and changes to one of them are not reflected by the other.
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A struct cannot be
null, although it can used as a nullable type:Vector v1 = null; //illegal Vector? v2 = null; //OK Nullable<Vector> v3 = null // OK -
Structs can be instantiated with or without using the
newoperator.//Both of these are acceptable Vector v1 = new Vector(); v1.X = 1; v1.Y = 2; v1.Z = 3; Vector v2; v2.X = 1; v2.Y = 2; v2.Z = 3;However, the
newoperator must be used in order to use an initializer:Vector v1 = new MyStruct { X=1, Y=2, Z=3 }; // OK Vector v2 { X=1, Y=2, Z=3 }; // illegal
A struct can declare everything a class can declare, with a few exceptions:
- A struct cannot declare a parameterless constructor.
structinstance fields can be set via a parameterized constructor or individually afterstructconstruction. Private members can only be initialized by the constructor. - A struct cannot declare members as protected, since it is implicitly sealed.
- Struct fields can only be initialized if they are const or static.
