structure vs class initialization via reference diff ?

Hello friends

Below mentioned code is working good but doubt is while object reference is created to class object vs structure object .

when calling variable using refernce.variable i am getting 100 in class i.e but in structure i am getting 10 as output ??

Is there anything related to value & reference mechanism of structures & class respectively .

If so can you please do explain me the internal process in depth & i hope this the the major difference when comes to class & structures :)

using System;

namespace codefile1

{

public class ClassPoint

{

public int X;

public int Y;

public ClassPoint(int a, int b)

{

X = a;

Y = b;

}

public struct StructPoint

{

public int X;

public int Y;

public StructPoint(int a, int b)

{

X = a;

Y = b;

}

public class Test

{

static void Main()

{

ClassPoint a = new ClassPoint(10, 10);

ClassPoint b = a;

a.X = 100;

StructPoint c = new StructPoint(10, 10);

StructPoint d = c;

c.X = 100;

Console.WriteLine( b.X.ToString() + "," + d.X );

Console.ReadLine();

}

Out put : 100,10

Ty for help

ClassPoint is a reference type and consequently the variable 'a' contains a reference to where the new ClassPoint object is stored. It doesn't contain the object itself.

This line:

ClassPoint b = a;

assigns the reference which 'a' contains to 'b'. Consequently, both 'a' and 'b' now refer to the same ClassPoint object.

This line:

a.X = 100;

changes the ClassPoint object's 'X' field to 100.

As it refers to the same object, b.X will also now give 100.

Looking now at the StructPoint struct which is a value type, this line:

StructPoint c = new StructPoint(10, 10);

creates a new instance of the struct and assigns it to the variable 'c'. However, 'c' contains the actual struct, not a reference to it.

This line:

StructPoint d = c;

creates a copy of the struct and assigns it to 'd'. Notice that this struct is now independent of the one contained in 'c'.

Finally, this line:

c.X = 100;

change's the X field of the StructPoint instance contained in 'c' to 100. It doesn't change d.X which still has its original value of 10.

This explains why the output is 100, 10.

1 Reply

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Vulpes13y ago
Accepted answer
ClassPoint is a reference type and consequently the variable 'a' contains a reference to where the new ClassPoint object is stored. It doesn't contain the object itself.

This line:

ClassPoint b = a;

assigns the reference which 'a' contains to 'b'. Consequently, both 'a' and 'b' now refer to the same ClassPoint object.

This line:

a.X = 100;

changes the ClassPoint object's 'X' field to 100.

As it refers to the same object, b.X will also now give 100.

Looking now at the StructPoint struct which is a value type, this line:

StructPoint c = new StructPoint(10, 10);

creates a new instance of the struct and assigns it to the variable 'c'. However, 'c' contains the actual struct, not a reference to it.

This line:

StructPoint d = c;

creates a copy of the struct and assigns it to 'd'. Notice that this struct is now independent of the one contained in 'c'.

Finally, this line:

c.X = 100;

change's the X field of the StructPoint instance contained in 'c' to 100. It doesn't change d.X which still has its original value of 10.

This explains why the output is 100, 10.