関数

COBOL の関数

method-id TestFunc.
   procedure division using by value x as binary-long,
                            by reference y as binary-long,
                            output z as binary-long.
      add 1 to x, y
      move 5 to z
end method.

01 a binary-long value 1.
01 b binary-long value 1.
01 c binary-long.  *> c doesn't need initializing

invoke self::TestFunc(value a reference b output c)
*> Or
invoke self::TestFunc(a b c)
display a space b space c

*> sum is an intrinsic function in COBOL
01 total binary-long.
set total to function sum(4 3 2 1) *> returns 10

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

*> then to call it:
method-id main.
    01 i binary-long.
    set i to self::MySum(1 2 3 4)
    display i
end method.

*> COBOL doesn't support optional arguments/parameters.
*> Just create two different versions of the same function.
method-id SayHello.
   procedure division using by value nam as string, prefix as string.
   display "Greetings, " prefix space nam
end method SayHello.

method-id SayHello.
   procedure division using by value nam as string.
   invoke self::SayHello(nam "")
end method.

C# の関数

// 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# doesn't support optional arguments/parameters.
   Just create two different versions of the same function. */
void SayHello(string name, string prefix)
{
   Console.WriteLine("Greetings, " + prefix + " " + name);
}

void SayHello(string name)
{
   SayHello(name, "");
}

VB.NET の関数

' 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













' Optional parameters must be listed last and must have a default value
Sub SayHello(ByVal name As String, Optional ByVal prefix As String = "")
  Console.WriteLine("Greetings, " & prefix & " " & name)
End Sub

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

これらの例の一部は、ハーディング大学コンピューター サイエンス学部の Frank McCown 博士が作成したもので、クリエイティブ コモンズ ライセンスに基づいて使用が許可されています。