Swap

Question

How do i swap the values of two integer variables?

Answer 1

int a=0, b=1;
1) int temp=a;
a=b;
b=temp;
2)a ^= b;
b ^= a;
a ^= b;
3) (a, b)=(b, a);
UPD https://www.sololearn.com/Profile/4528074/?ref=app method
4)a+=b;
b=a-b;
a-=b;

Answer 2

Brian Tuple Deconstruction is one of several new language features that came out with C# 7.

You might find this detailed review of tuple deconstruction interesting:

https://github.com/dotnet/roslyn/blob/master/docs/features/deconstruction.md

To get a sense of the other awesome features that came out with C# 7, take a look at this link:

https://docs.microsoft.com/en-us/dotnet/csharp/whats-new/csharp-7

Oh heck... it's worth checking these out as well:

https://docs.microsoft.com/en-us/dotnet/csharp/whats-new/csharp-8

- Continues expanding support for pattern matching in a static typed language.

https://docs.microsoft.com/en-us/dotnet/csharp/whats-new/csharp-9

- Top Level Statements is a standout feature that removes the verbosity of specifying the namespace, class, and static main method.

C# is such an expressive language, it's difficult for me to find as much joy coding in any other static typed language.

Kotlin may be the closest to C# for me in this regards.

Sorry for the tangent. 🙏

Answer 3

Brian We're still stuck on C# 7 for our applications as. I want to use features of C# 8 so badly. Hopefully, we'll get the upgrades in with an upcoming tech debt sprint?

I'm still unpacking the awesome features of C# 9 and just discovered support for covariant return types. Mind is blown! 🤯😂

Seriously though... overloading methods based on different return types have huge potential for making code even more concise.

https://daveabrock.com/2020/07/14/c-sharp-9-target-typing-covariants#:~:text=With%20return%20type%20covariance%2C%20you,returns%20a%20more%20specific%20type.&text=Now%2C%20you%20can%20return%20the%20more%20specific%20type%20in%20C%23%209.

Answer 4

Brian, you're wrong
https://code.sololearn.com/cQCtAX0Y4tr8/?ref=app

Answer 5

David Carroll thank you, much! My C# knowledge is definitely a couple revisions old. My last workplace was reluctant to upgrade.

Answer 6

I've seen people use method #2 and #4 also seen people say it doesn't always work (forgot the why). So beginner context, take method #1, or #3 which looks pretty neat (so long as the framework was updated).

Hats off David Carroll for the updates links, fresh from the oven 🙏

Answer 7

𝔸𝕞𝕒𝕟𝕓𝕖𝕜 𝕆𝕣𝕪𝕟𝕓𝕒𝕪 I see clearly that I am wrong. I did try to prove it to myself before posting, and I got a syntax error. Thank you for showing me something new!

So, add my suggestion as number 4.

Answer 8

Brian
Right, I remember slightly someone mentioned that. So how about negative numbers support in #2 and #4? are they all good for it?

I still think #1 is the clearest and simple method, especially for beginners. Though we've all seen people asking how to do swaps without interim storage, many a time here #scratchinghead#

Answer 9

Big Thanks Brian 🙏

Answer 10

Thanks 🤗

Answer 11

𝔸𝕞𝕒𝕟𝕓𝕖𝕜 𝕆𝕣𝕪𝕟𝕓𝕒𝕪 option 3) is valid in Python, but not in C#. May I suggest a replacement for 3?

3) a += b;
b = a - b;
a -= b;

EDIT: Oops, 3) IS valid in C# after all!

Answer 12

Brian, ok :)

Answer 13

Ipang #2 would not work for floating point numbers, unless they were cast to an equivalent-sized integer type.

And #4 would be unreliable for floating point numbers due to floating point math issues, magnitude truncation, et al. Also, #4 may cause overflow in any data type if the sum of a+b is too large.

Answer 14

Ipang negative integers should work just fine with all the methods, including #2 and #4 (while heeding the warning about a+b overflow).

I fully agree that #1 is the most universal and recommended solution. It is good for all data types, value ranges, and not limited to any particular language.