Functions, Methods - in COBOL and C# and VB.NET

// Pass by value (in, default), reference (in/out), and reference (out)
void TestFunc(int x, ref int y, out int z)
{
   x++;
   y++;
   z = 5;
}

int a = 1, b = 1, c;  // c doesn't need initializing
TestFunc(a, ref b, out c);
Console.WriteLine("{0} {1} {2}", a, b, c);  // 1 2 5
// Accept variable number of arguments
int Sum(params int[] nums)
{
  int sum = 0;
  foreach (int i in nums)
  {
      sum += i;
  }
  return sum;
}

int total = Sum(4, 3, 2, 1);   // returns 10

// C# supports optional arguments/parameters.
// The default value is specified with the syntax '= value'.
// Optional parameters must be listed last.
void SayHello(string name, string prefix = "")
{
   Console.WriteLine("Greetings, " + prefix + " " + name);
}

class-id Functions.
*> Pass by value (in, default), reference (in/out), and reference (out)
method-id TestFunc (x as binary-long,
                    reference y as binary-long,
                    output z as binary-long).
      add 1 to x, y
      move 5 to z
end method.

method-id InstMethod.
    declare a as binary-long = 1
    declare b as binary-long = 1
    declare c as binary-long
    invoke TestFunc(value a reference b output c)
    *> Or
    invoke self::TestFunc(a b c)
    display a space b space c

    declare total as binary-long
    *> Commas in parameter lists are optional
    set total to function sum(4 3 2 1) *> returns 10
    display total
end method.

method-id main static.
    declare i as binary-long
    set i to MySum(1 2 3 4)
    display i
    declare o = new self

    *> Parentheses are optional when there are no parameters.
    invoke o::InstMethod
    invoke SayHello("Strangelove", "Dr.")
    invoke SayHello("Madonna")
end method.

*> To create a non intrinsic variable argument list function:
method-id MySum static (params nums as binary-long occurs any)
                      returning mysum as binary-long.
    perform varying i as binary-long through nums
        add i to mysum
    end-perform
end method.

*> COBOL supports optional arguments/parameters.
*> The default value is specified with the syntax '= value'.
*> Optional parameters must be listed last.
method-id SayHello static (nam as string,
                           prefix as string = "").
      display "Greetings, " prefix space nam
end method.

end class.

' Pass by value (in, default), reference (in/out), and reference (out)
Sub TestFunc(ByVal x As Integer,
             ByRef y As Integer,
             ByRef z As Integer)
  x += 1
  y += 1
  z = 5
End Sub


Dim a = 1, b = 1, c As Integer   ' c set to zero by default
TestFunc(a, b, c)
Console.WriteLine("{0} {1} {2}", a, b, c)   ' 1 2 5
' Accept variable number of arguments
Function Sum(ByVal ParamArray nums As Integer()) As Integer
  Sum = 0
  For Each i As Integer In nums
    Sum += i
  Next
End Function   ' Or use Return statement like C#

Dim total As Integer = Sum(4, 3, 2, 1)   ' returns 10

' VB.NET supports optional arguments/parameters.
' The default value is specified with the syntax '= value',
' though optional parameters must be explicitly marked as such.
' Optional parameters must be listed last.
Sub SayHello(ByVal name As String,
             Optional ByVal prefix As String = "")
  Console.WriteLine("Greetings, " & prefix & " " & name)
End Sub

SayHello("Strangelove", "Dr.")
SayHello("Madonna")