C # value type and reference type parameter [basic]

 

According to the parameter type and transmission mode, there are four different situations:
Value Type parameter passing by value; (INT m)

Pass the reference type parameter by value (address value); (string Str)

Value Type parameter passed by reference; (ref int m)

Transmit parameters of the reference type by reference; (ref string Str)

 

Parameter of value type and reference type

Class Demo
{
Static   Void Main ( String [] ARGs)
{
Int N =   100 ;
String Str =   " One " ;

Changebyvalue ( Ref N ); // Value Type: ref transmits the address of Variable N (that is, the address of value type)
Changebyref ( Ref Str ); // Reference Type: ref transmits the STR address (that is, the reference) of the variable)

Console. writeline (N );
Console. writeline (STR );
}
Private   Static   Void Changebyvalue ( Ref   Int M)
{
M =   200 ; // Actually, it changes the value of Variable N.
}
Private   Static   Void Changebyref ( Ref   String S)
{
S =   " Two " ;
}

// Through, the parameter with ref (or out), and the method without REF (or out) can be overloaded.
Private   Static   Void Changebyref ( String S)
{
S =   " Two " ;
}

//Error: you cannot define a different overload method on ref and out.
//Cause: In msil, ref and out are of the same type.
/*Private Static void changebyref (out string S)
{
S = "two ";
}
*/ 
}