C#•2y ago

pointers help

i want to make a function that swaps two ints using pointers but i get an error with the declaration of the function

14 Replies

max2451OP•2y ago

this is mi code:

using System;

namespace Main {
    class Program {
        static void Main(string[] args) {
            int a = 12;
            int b = 21;

            Console.WriteLine("a: {0} || b: {1}", a, b);
            
            Console.WriteLine("a: {0} || b: {1}", a, b);
        }

        unsafe void Swap(int* a, int* b) {
            int temp;
            temp = *b;
            *b = *a;
            *a = *b;
        }
    }
}

using System;

namespace Main {
    class Program {
        static void Main(string[] args) {
            int a = 12;
            int b = 21;

            Console.WriteLine("a: {0} || b: {1}", a, b);
            
            Console.WriteLine("a: {0} || b: {1}", a, b);
        }

        unsafe void Swap(int* a, int* b) {
            int temp;
            temp = *b;
            *b = *a;
            *a = *b;
        }
    }
}

TheBoxyBear•2y ago

What is the error? Also for this purpose, I would recommend ref instead of pointers

max2451OP•2y ago

it says Unsafe code may only appear if compiling with /unsafe what are refs?

TheBoxyBear•2y ago

You need to enable unsafe code in the project properties

Anton•2y ago

set AllowUnsafeBlocks to true

TheBoxyBear•2y ago

https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/ref This doesn't require unsafe

ref keyword - C# Reference

Anton•2y ago

or with tuples: (a, b) = (b, a)

max2451OP•2y ago

how do i do that?

Anton•2y ago

set that property to true in your csproj file

arion•2y ago

The tag will looks like this.

arion•2y ago

https://cdn.discordapp.com/attachments/883435300880261120/1062163515886014494/2f59ab03-4147-4aad-9dd2-92ce66369d60_10-01-2023.png

arion•2y ago

Though as Boxy said, the ref keyword doesn't require unsafe and does pretty much the same thing, its even marshalled into native code as a pointer i believe I believe the out keyword is also marshalled the same as a parameter return type

Connor•2y ago

This is really unnecessary for what it’s trying to accomplish

FusedQyou•2y ago

I wonder what the point of this is anyway. I feel like an explanation why you need this in general is needed It's very rare you actually need pointers

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pointers help