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  4. Pass by value and pass by reference

Pass by value and pass by reference

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  • S Sherin Iranimose

    After the function call its printing 30, That is the matter :)

    EVEN THE WORD IMPOSSIBLE SAYS I M POSSIBLE. How to post a question

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    Paul Conrad
    wrote on last edited by
    #15

    For some reason, I sense you are asking a programming question. That is a big NO in this particular forum.

    "The clue train passed his station without stopping." - John Simmons / outlaw programmer "Real programmers just throw a bunch of 1s and 0s at the computer to see what sticks" - Pete O'Hanlon

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    • S Sherin Iranimose

      namespace SampleCSharp { public class MyClass { public int myVar; } public class SampleClass { private void SampleClass_Load(object sender, EventArgs e) { MyClass objMyClass = new MyClass(); objMyClass.myVar = 10; ChangeMyVar(objMyClass);//**IS THIS PASS BY VALUE OR PASS BY REFERENCE** } public void ChangeMyVar(MyClass objMyClass) { objMyClass.myVar = 30; } } }

      EVEN THE WORD IMPOSSIBLE SAYS I M POSSIBLE.

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      Joe Woodbury
      wrote on last edited by
      #16

      This appears to be C# code. Classes are passed by reference by design.

      Anyone who thinks he has a better idea of what's good for people than people do is a swine. - P.J. O'Rourke

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      • CPalliniC CPallini

        V. wrote:

        objects (including strings) are passed by reference to my knowledge

        Nope. All parameters are passed by value. you should use the ref keyword to pass a parameter by reference. BTW: passing by value an object implies that called function can actually change object's internal state. :)

        If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
        This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong. -- Iain Clarke
        [My articles]

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        Joe Woodbury
        wrote on last edited by
        #17

        This is incorrect. Classes are passed by reference, Structs are passed by value.

        CPallini wrote:

        BTW: passing by value an object implies that called function can actually change object's internal state. [Smile]

        This means nothing of the sort. Passing by value simply means that an object in a method is distinct from the original object and any changes made to that object are not reflected in the original.

        Anyone who thinks he has a better idea of what's good for people than people do is a swine. - P.J. O'Rourke

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        • J Joe Woodbury

          This is incorrect. Classes are passed by reference, Structs are passed by value.

          CPallini wrote:

          BTW: passing by value an object implies that called function can actually change object's internal state. [Smile]

          This means nothing of the sort. Passing by value simply means that an object in a method is distinct from the original object and any changes made to that object are not reflected in the original.

          Anyone who thinks he has a better idea of what's good for people than people do is a swine. - P.J. O'Rourke

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          CPallini
          wrote on last edited by
          #18

          You are wrong. Whenever you pass an object, a reference to the object's instance is passed by value. :)

          If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
          This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong. -- Iain Clarke
          [My articles]

          In testa che avete, signor di Ceprano?

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          • S Sherin Iranimose

            namespace SampleCSharp { public class MyClass { public int myVar; } public class SampleClass { private void SampleClass_Load(object sender, EventArgs e) { MyClass objMyClass = new MyClass(); objMyClass.myVar = 10; ChangeMyVar(objMyClass);//**IS THIS PASS BY VALUE OR PASS BY REFERENCE** } public void ChangeMyVar(MyClass objMyClass) { objMyClass.myVar = 30; } } }

            EVEN THE WORD IMPOSSIBLE SAYS I M POSSIBLE.

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            KarstenK
            wrote on last edited by
            #19

            I guess it gets passed by reference because it is C#. :rolleyes: In C++ by value.

            Greetings from Germany

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            • S Sherin Iranimose

              namespace SampleCSharp { public class MyClass { public int myVar; } public class SampleClass { private void SampleClass_Load(object sender, EventArgs e) { MyClass objMyClass = new MyClass(); objMyClass.myVar = 10; ChangeMyVar(objMyClass);//**IS THIS PASS BY VALUE OR PASS BY REFERENCE** } public void ChangeMyVar(MyClass objMyClass) { objMyClass.myVar = 30; } } }

              EVEN THE WORD IMPOSSIBLE SAYS I M POSSIBLE.

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              Mitendra Anand
              wrote on last edited by
              #20

              Value-type objects such as structs are created on the stack, while reference-type objects such as classes are created on the heap. So it is actually a PASS - BY - REFERENCE Both types of objects are destroyed automatically, but objects based on value types are destroyed when they go out of scope, whereas objects based on reference types are destroyed at an unspecified time after the last reference to them is removed. Happy Coding! Mitendra

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              • P Pete OHanlon

                It's passed by the lower intestinal tract.

                Deja View - the feeling that you've seen this post before.

                My blog | My articles

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                Muigai Mwaura
                wrote on last edited by
                #21

                I'm cracking up :laugh: I'm shedding tears :(( the people I work with are looking at me like I'm crazy.

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                • M Mitendra Anand

                  Value-type objects such as structs are created on the stack, while reference-type objects such as classes are created on the heap. So it is actually a PASS - BY - REFERENCE Both types of objects are destroyed automatically, but objects based on value types are destroyed when they go out of scope, whereas objects based on reference types are destroyed at an unspecified time after the last reference to them is removed. Happy Coding! Mitendra

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                  jon_175
                  wrote on last edited by
                  #22

                  The object is passed by value, but the what is actually passed since it is a reference object is a pointer to the object. So, the "value" that is actually passed is the pointer not the object and therefore any changes made through the pointer change the original object. What you can't change is the pointer itself. That is the "value". :)

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                  • J jon_175

                    The object is passed by value, but the what is actually passed since it is a reference object is a pointer to the object. So, the "value" that is actually passed is the pointer not the object and therefore any changes made through the pointer change the original object. What you can't change is the pointer itself. That is the "value". :)

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                    Mitendra Anand
                    wrote on last edited by
                    #23

                    You are right Jon. I see your point.

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                    • S Sherin Iranimose

                      So If I print the value anywhere inside the Load function will only print 10. But it is not.... Its 30 after function call.

                      EVEN THE WORD IMPOSSIBLE SAYS I M POSSIBLE. How to post a question

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                      BillW33
                      wrote on last edited by
                      #24

                      When the class object is passed into ChangeMyVar(MyClass objMyClass) it is passed by value. Saying it another way: a copy of the object is made and then used by the ChangeMyVar method. Since this is a copy any changes to it do not affect the original. Bill W

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