Call-by-value, call-by-reference (C#)

by value:

static void u (int x) { x = x + 1; }
int y = 3 ; u (y); 
Console.WriteLine(y); // 3

by reference:

static void u (ref int x) { x = x + 1; }
int y = 3 ; u (ref y); 
Console.WriteLine(y); // 4

Übung: ref/kein ref; struct (Werttyp)/class (Verweistyp)

class C { public int foo }
static void u (ref C x) { x.foo=4; x=new C{foo=5};}
C y = new C {foo=3} ; C z = y; u (ref y);
Console.WriteLine(y.foo + " " + z.foo);