Shallow Copy and Deep Copy in C#
Last Updated :
17 Jul, 2024
In general, when we try to copy one object to another object, both the objects will share the same memory address. Normally, we use assignment operator, = , to copy the reference, not the object except when there is value type field. This operator will always copy the reference, not the actual object. For Example: Suppose G1 refers to memory address 5000 then G2 will also refer to 5000. So if one will change the value of data stored at address 5000 then both G1 and G2 will show the same data.
Geeks G1 = new Geeks();
// Copy the instance using
// '=' operator
Geeks G2 = G1;
Shallow Copy:
Creating a new object and then copying the
value type
fields of the current object to the new object. But when the data is
reference type
, then the only reference is copied but not the referred object itself. Therefore the original and clone refer to the same object. The concept will more clear when you will see the code and the diagram of the Shallow copy.
Note: In the above diagram The Global Rank is value type field so it creates the copy of that and store it in different location but the Name (Desc) is Reference type field so it’s pointing to the old or main memory location.
Example:Here, if you will change value type then it is working on c2 and c1, and not affected but in reference type any change will affect both c1 and c2.
Csharp
// C# program to illustrate the
// concept of Shallow Copy
using System;
class Example {
// Main Method
static void Main(string[] args)
{
Company c1 = new Company(548, "GeeksforGeeks",
"Sandeep Jain");
// Performing Shallow copy
Company c2 = (Company)c1.Shallowcopy();
Console.WriteLine("Before Changing: ");
// Before changing the value of c2 GBRank and
// CompanyName
Console.WriteLine(c1.GBRank);
Console.WriteLine(c2.GBRank);
Console.WriteLine(c2.desc.CompanyName);
Console.WriteLine(c1.desc.CompanyName);
// changing the value of c2 GBRank and CompanyName
c2.GBRank = 59;
c2.desc.CompanyName = "GFG";
Console.WriteLine("\nAfter Changing: ");
// After changing the value of c2 GBRank and
// CompanyName
Console.WriteLine(c1.GBRank);
Console.WriteLine(c2.GBRank);
Console.WriteLine(c2.desc.CompanyName);
Console.WriteLine(c1.desc.CompanyName);
}
}
class Company {
public int GBRank;
public CompanyDescription desc;
public Company(int gbRank, string c, string o)
{
this.GBRank = gbRank;
desc = new CompanyDescription(c, o);
}
// method for cloning object
public object Shallowcopy()
{
return this.MemberwiseClone();
}
// method for cloning object
public Company DeepCopy()
{
Company deepcopyCompany = new Company(
this.GBRank, desc.CompanyName, desc.Owner);
return deepcopyCompany;
}
}
class CompanyDescription {
public string CompanyName;
public string Owner;
public CompanyDescription(string c, string o)
{
this.CompanyName = c;
this.Owner = o;
}
}
OutputBefore Changing:
548
548
GeeksforGeeks
GeeksforGeeks
After Changing:
548
59
GFG
GFG
Deep Copy:
It is a process of creating a new object and then copying the fields of the current object to the newly created object to make a complete copy of the internal reference types. If the specified field is a value type, then a bit-by-bit copy of the field will be performed. If the specified field is a reference type, then a new copy of the referred object is performed.
Note: In the above diagram The Global Rank is value type field so it creates the copy of that and store it in different location. The Name(Desc) is Reference type field so in Deep Copy there is a clone of reference type field which also will be stored in a different location.
Example: Here, the field type does not matter whether it is value type or reference type. Deep copy makes a copy of whole data and store it in a different memory location so if we change c2, c1 will not affected vice versa also.
Csharp
// C# program to demonstrate the
// concept of Deep copy
using System;
namespace ShallowVSDeepCopy {
class Program {
// Main Method
static void Main(string[] args)
{
Company c1 = new Company(548, "GeeksforGeeks",
"Sandeep Jain");
// Performing Deep copy
Company c2 = c1.DeepCopy();
Console.WriteLine("Before Changing:");
// Before changing the value of c2 GBRank and
// CompanyName
Console.WriteLine("c1.GBRank: " + c1.GBRank);
Console.WriteLine("c2.GBRank: " + c2.GBRank);
Console.WriteLine("c1.CompanyName: "
+ c1.desc.CompanyName);
Console.WriteLine("c2.CompanyName: "
+ c2.desc.CompanyName);
Console.WriteLine("\nAfter Changing:");
// changing the value of c2 GBRank and CompanyName
c2.GBRank = 59;
c2.desc.CompanyName = "GFG";
// After changing the value of c2 GBRank and
// CompanyName
Console.WriteLine("c1.GBRank: " + c1.GBRank);
Console.WriteLine("c2.GBRank: " + c2.GBRank);
Console.WriteLine("c1.CompanyName: "
+ c1.desc.CompanyName);
Console.WriteLine("c2.CompanyName: "
+ c2.desc.CompanyName);
}
}
class Company {
public int GBRank;
public CompanyDescription desc;
public Company(int gbRank, string companyName,
string owner)
{
this.GBRank = gbRank;
desc = new CompanyDescription(companyName, owner);
}
// Method for deep copying object
public Company DeepCopy()
{
return new Company(this.GBRank,
this.desc.CompanyName,
this.desc.Owner);
}
}
class CompanyDescription {
public string CompanyName;
public string Owner;
public CompanyDescription(string companyName,
string owner)
{
this.CompanyName = companyName;
this.Owner = owner;
}
}
}
OutputBefore Changing:
c1.GBRank: 548
c2.GBRank: 548
c1.CompanyName: GeeksforGeeks
c2.CompanyName: GeeksforGeeks
After Changing:
c1.GBRank: 548
c2.GBRank: 59
c1.CompanyName: GeeksforGeeks
c2.CompanyName: G...