Using this Reference

Question

It is said that using this reference can save memory. Can anyone please explin how "this" can save memory. Following one is a example program.

using System;
public class CreateStudent
{
public static void Main()
{
Student x = new Student();

x.SetId(951);
x.SetName("Ross");
x.SetGPA(3.5);

Console.WriteLine
("The student named {0} has ID # is {1} and a gpa of {2}", x.GetName(), x.GetId(), x.GetGPA());

Console.ReadLine();
}
}
class Student
{
private int id;
private string lastName;
private double gpa;

public int GetId()
{
return id;
}
public void SetId(int id)
{
this.id = id;
}

public string GetName()
{
return lastName;
}
public void SetName(string lastName)
{
this.lastName = lastName;
}

public double GetGPA()
{
return gpa;
}
public void SetGPA(double gpa)
{
this.gpa = gpa;
}
}
//The student named Ross has ID # is 951 and a gpa of 3.5

Maha · Answer

Thank you for your help

Vulpes · Answer

The advantage of the original program was that you were able to give your fields or local variables the names you would have naturally preferred to give them. You've now had to change one or the other of them to something else to avoid the conflict which the 'this' keyword was resolving.

Maha · Answer

Above program is rewritten without using this reference. Please tell me the advantages of using this reference in this program. using System; public class CreateStudent { public static void Main() { Student x = new Student(); x.SetId(951); x.SetName(Ross); x.SetGPA(3.5); Console.WriteLine (The student named {0} has ID # is {1} and a gpa of {2} x.GetName() x.GetId() x.GetGPA()); Console.ReadLine(); } } class Student { private int idNumber; private string lastName; private double gradePointAverage; public int GetId() { return idNumber; } public void SetId(int id) { idNumber = id; } public string GetName() { return lastName; } public void SetName(string name) { lastName = name; } public double GetGPA() { return gradePointAverage; } public void SetGPA(double gpa) { gradePointAverage = gpa; } } //The student named Ross has ID # is 951 and a gpa of 3.5

Vulpes · Answer

It has several good uses: 1. To distinguish one of a class's fields from a local variable or parameter of the same name within a method or property of that class. 2. In the case of an instance constructor to chain to another instance constructor of the same class but with a different signature. 3. To distinguish an extension method from an ordinary static method - the former requires the first parameter to be decorated with 'this' to indicate the type of object the method is extending. 4. To declare indexers. 5. To pass a reference to the current object as a parameter to a method.

Maha · Answer

So what is the purpose of using this reference.

Vulpes · Answer

For the life of me I can't understand how it can save memory as if you don't use it in the source code the compiler will insert it in the IL. So it doesn't make any difference if you use it or not. Also all instance methods take a hidden 'this' reference as their first parameter. However where it is needed is to distinguish between a field and a local variable of the same name. That situation occurs in several places in your code.

Using "this" Reference