C# Structs
Description
A struct is similar to a class, with the following key differences:
- A struct is a value type, whereas a class is a reference type.
- A struct does not support inheritance.
A struct can have all the members a class can, except the following:
- A parameterless constructor
- A finalizer
- Virtual members
A struct is used when value-type semantics are desirable.
Because a struct is a value type, each instance does not require instantiation.
Syntax
A struct is similar to a class, but is a value type, not a reference type. Here is the general form of a struct:
struct name : interfaces {
// member declarations
}
Example
Here is an example of declaring and calling struct constructors:
/*from w w w . jav a 2s . c o m*/
public struct Point
{
int x, y;
public Point (int x, int y) { this.x = x; this.y = y; }
}
Point p1 = new Point (); // p1.x and p1.y will be 0
Point p2 = new Point (1, 1); // p1.x and p1.y will be 1
Example 2
A simple struct with method
using System;/*www . j a va 2 s.c o m*/
struct Fraction {
public int numerator;
public int denominator;
public void Print( ) {
Console.WriteLine( "{0}/{1}", numerator, denominator );
}
}
public class MainClass {
public static void Main( ) {
Fraction f;
f.numerator = 5;
f.denominator = 10;
f.Print( );
Fraction f2 = f;
f.Print( );
f2.numerator = 1;
f.Print( );
f2.Print( );
}
}
The code above generates the following result.
Example 3
using System;// ww w. ja va 2 s .co m
public struct Square
{
public int Width
{
get
{
return width;
}
set
{
width = value;
}
}
public int Height
{
get
{
return height;
}
set
{
height = value;
}
}
private int width;
private int height;
}
public class MainClass
{
static void Main()
{
Square sq = new Square();
sq.Width = 1;
sq.Height = 1;
}
}
The code above generates the following result.
Example 4
using System;// www . j av a2s .c o m
struct Number: IComparable
{
int value;
public Number(int value)
{
this.value = value;
}
public int CompareTo(object obj2)
{
Number num2 = (Number) obj2;
if (value < num2.value)
return(-1);
else if (value > num2.value)
return(1);
else
return(0);
}
}
class MainClass
{
public static void Main()
{
Number x = new Number(3);
Number y = new Number(4);
IComparable Ic = (IComparable) x;
Console.WriteLine("x compared to y = {0}", Ic.CompareTo(y));
}
}
The code above generates the following result.
