编辑代码

using System;

public class HelloWorld
{
    public static void Main()
    {
        int a=15;
        int b=30;
        fun1(ref a, ref b);
        
        console.WriterLine(a);
        console.WriterLine(b);
    }
    public static void fun1( ref a,ref b){
        int temp =a;
        a=b;
        b=temp;
    }
}