Ref reference type, array parameter, out output parameter

Similarities and differences between ref and out

Commonalities: All references are passed.
Difference: the ref parameter must be assigned a value before being called. You can leave no value during method calling.
The out parameter can be assigned no value before being called. It must be assigned a value during the method call process.

 

// Method parameters
Class Program
{
Static void main (string [] ARGs)
{
// Value transfer
// Int num = 5;
// Change (Num );
// Console. writeline ("Num in the main method is:" + num );

// Reference Transmission
// Int [] arr = {1, 3, 5 };
// Change (ARR );
// Console. writeline ("arr [1] In the main method is:" + arr [1]);

// Ref parameter (reference transfer)
// Int num = 5;
// Change (ref num); // The ref parameter must be assigned a value before calling.
// The num in the console. writeline ("Main (REF) method is:" + num );

// Out parameter (reference transfer)
// Int num;
// Outchange (Out num );
// The num in the console. writeline ("Main (out) method is:" + num );

// Array parameters (transfer by reference)
Int result = sum ("*", 3, 5, 6 );
Console. writeline (result );
}

Public static void change (INT number)
{
Number = 10;
Console. writeline ("number in change is:" + number );
}

Public static void change (INT [] ARR)
{
Arr [1] = 100;
Console. writeline ("arr [1] In change is:" + arr [1]);
}

Public static void change (ref int number)
{
Number = 10;
Number in console. writeline ("Change (ref parameter) is:" + number );
}

Public static void outchange (Out int number)
{
Number = 20;
Console. writeline ("outchange (out parameter) in number:" + number );
}

// Note: array parameters must be placed at the end of the parameter list
Public static int sum (string op, Params int [] num)
{
If (OP = "+ ")
{
Int Total = 0;
For (INT I = 0; I <num. length; I ++)
{
Total + = num [I];
}
Return total;
}
Else if (OP = "*")
{
Int Total = 1;
For (INT I = 0; I <num. length; I ++)
{
Total * = num [I];
}
Return total;
}
Else
{
Console. writeline ("the operator can only be + /*");
Return-1;
}

}
}