C#

1nsp1r3d wrote:

As I was reading C# Language Pocket Reference, it says that all parameters are passed by value(ASAIK the book targets .NET 1.0).

1nsp1r3d wrote:

I thought that all reference types were passed by reference and all value types by value(enums and ints/floats/etc)? Is that the case?

public void SomeMethod(string name)
{
    name = "B";

    // Local name now points to "B"
}

//...

string name = "A";

SomeMethod(name);

// name still references "A"

public void SomeMethod(ref string name)
{
    name = "B";

    // name points to "B"
}

//...

string name = "A";

SomeMethod(ref name);

// name now points to "B"

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"Man who stand on hill with mouth open will wait long time for roast duck to drop in." -- Confucious

1nsp1r3d wrote:

I thought that all reference types were passed by reference and all value types by value(enums and ints/floats/etc)? Is that the case?

using System;
 
namespace ConsoleApplication12
{
    class A
    {
        private string someValue;

        public string SomeValue
        {
            get
            {
                return this.someValue;
            }
            set 
            {
                this.someValue = value;
            }
        }
    }
 
    class Class1
    {
        [STAThread]
        static void Main(string[] args)
        {
            Console.WriteLine("In the Main method");
            A mainA = new A();
            mainA.SomeValue = "This was set in the main method";
            Console.WriteLine(mainA.SomeValue);
            AnotherMethod(mainA);
            Console.WriteLine(mainA.SomeValue);
            Console.ReadLine();
        }
 
        static void AnotherMethod(A parameterA)
        {
            Console.WriteLine("In AnotherMethod");
            Console.WriteLine(parameterA.SomeValue);
            parameterA.SomeValue = "This value was set in AnotherMethod";
            Console.WriteLine(parameterA.SomeValue);
            Console.WriteLine("Exiting AnotherMethod");
        }
    }
}

In the Main method
This was set in the main method
In AnotherMethod
This was set in the main method
This value was set in AnotherMethod
Exiting AnotherMethod
This value was set in AnotherMethod

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"Man who stand on hill with mouth open will wait long time for roast duck to drop in." -- Confucious

Colin Angus Mackay wrote:

As you can see, the object of class A is passed by reference because when its property is updated in the method, the update is reflected in the Main method after the call.

static void AnotherMethod(A parameterA)        
{
    Console.WriteLine("In AnotherMethod");            
    Console.WriteLine(parameterA.SomeValue);            
    parameterA = new A();                    // Allocated new object.
    parameterA.SomeValue = "This value was set in AnotherMethod";               
    Console.WriteLine(parameterA.SomeValue);            
    Console.WriteLine("Exiting AnotherMethod");        
}

static void AnotherMethod(ref A parameterA)        
{
    Console.WriteLine("In AnotherMethod");            
    Console.WriteLine(parameterA.SomeValue);            
    parameterA = new A();                    // Allocated new object.
    parameterA.SomeValue = "This value was set in AnotherMethod";               
    Console.WriteLine(parameterA.SomeValue);            
    Console.WriteLine("Exiting AnotherMethod");        
}

My: Blog | Photos

"Man who stand on hill with mouth open will wait long time for roast duck to drop in." -- Confucious

Colin Angus Mackay wrote:

Anyway, everything's sorted out now.... I hope....

void SomeMethod(int *pointer)
{
    /* Allocate memory */
    pointer = malloc(42);
}

int *p;

SomeMethod(p);

/* Oops!!! The variable p doesn't point to anything! */
p[0] = 0;

void SomeMethod(int **pointer)
{
    /* Allocate memory */
    *pointer = malloc(42);
}

int *p;

SomeMethod(&p);

/* Yay! */
p[0] = 0;

Leslie Sanford wrote:

and my C is really rusty, so pardon me if this isn't exactly correct

Leslie Sanford wrote:

Well, hopefully some of that makes sense.

My: Blog | Photos

"Man who stand on hill with mouth open will wait long time for roast duck to drop in." -- Confucious

1nsp1r3d wrote:

I thought that all reference types were passed by reference and all value types by value(enums and ints/floats/etc)?

My: Blog | Photos

"Man who stand on hill with mouth open will wait long time for roast duck to drop in." -- Confucious

-- modified at 11:03 Thursday 24th November, 2005

Subrahmanyam K wrote:

decimal d = 45.52
lblNetPrice.Text = Convert.ToString(d);