what are the main usage of returning a value by refrence from a func?

mina shaker

3y947C#

i have been read about the ref keyword i understand the concept of returning the value by ref from a function using the ref keyword but what i didnt understand what are the usage of it why whould i use somthong like that

can any one help me in that

5 Replies

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Pankajkumar Patel3y ago
Accepted answer
Hi Mina Shaker,

The ref keyword indicates that a variable is a reference, or an alias for another object.

Used in five different contexts:
1. In a method signature and in a method call, to pass an argument to a method by reference. For more information, see Passing an argument by reference.
2. In a method signature, to return a value to the caller by reference. For more information, see Reference return values.
3. In a member body, to indicate that a reference return value is stored locally as a reference that the caller intends to modify. Or to indicate that a local variable accesses another value by reference. For more information, see Ref locals.
4. In a struct declaration, to declare a ref struct or a readonly ref struct. For more information, see the ref struct article.
5. In a ref struct declaration, to declare that a field is a reference. See the ref field article.
For more details:
- ref (C# Reference)
  
  https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/ref
Hope this will help you!
Pankajkumar Patel3y ago
Hi Mina Shaker,

"i know how to use them but i dont know what are the senarios that i shoud use this approches in"

The best example coming in my mind is a function to Swap two variables values:
```
static void Swap(ref T el1, ref T el2)
{
    var mem = el1;
    el1 = el2;
    el2 = mem;
}
```
Usage:
```
static void Main(string[] args)
{
    string a = "Hello";
    string b = "Hi";

    Swap(ref a, ref b);
    // now a = "Hi" b = "Hello"

    // it works also with array values:
    int[] arr = new[] { 1, 2, 3 };
    Swap(ref arr[0], ref arr[2]);
    // now arr = {3,2,1}
}
```
For more details:
- Example of practical of "ref" use
  
  https://stackoverflow.com/questions/4646159/example-of-practical-of-ref-use
Hope this will help you!
Vishal Yelve3y ago
Hi Mina,

Please check below link. for example of ref keyword

https://www.c-sharpcorner.com/UploadFile/mahakgupta/working-with-ref-and-out-parameter-in-C-Sharp/

https://www.tutorialsteacher.com/articles/ref-keyword
mina shaker3y ago
@Pankaj Patel

thank you for help but i know how to use them but i dont know what are the senarios that i shoud use this approches in
Abhishek Yadav3y ago
When returning a reference, be careful that the object being referred to does not go out of scope. So it is not legal to return a reference to local var. But you can always return a reference on a static variable.