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   ► KBTo/From GuidesDelphiStatements  Print This     

Cross Ref > Statements

By Mike Prestwood

Delphi versus C#: A side by side comparison between Delphi and C#.

 
Statements
 

Common statements such as if statements, loops, etc.

Exception Trapping

[Other Languages] 

Languages Focus

A common usage of exception handling is to obtain and use resources in a "try-it" block, deal with any exceptions in an "exceptions" block, and release the resources in some kind of "final" block which executes whether or not any exceptions are trapped.

Delphi:   try..except, try..finally

Use a try..except..end block to trap and process errors.

Delphi also offers a try...finally where code will execute in the finally section no matter what. It's common to put a try..except inside a try..finally.

Syntax Example:
var
y : Double;
begin
try
y := 0;
y := (1/y);
ShowMessage(FloatToStr(y));
except
ShowMessage('You cannot divide by zero.');
end;
end;
C#:   try...catch...finally

C# uses a try...catch...finally statement to trap for errors.

try {}
catch {}
finally {}
Syntax Example:
try
{
int y = 0;
y = 1 / y;
}
catch
{
MessageBox.Show("you cannot divide by zero");
}




If Statement

[Other Languages] 
Delphi:   If..Else If..Else

Notice in the more complete example that the semicolon for the begin..end block after end is not included. That tells the compiler something else is coming (the statement is not finished). Also note the semicolon is missing right before the final "else" statement.

Note: The following example uses floating point literals. In Delphi, to specify a fractional floating point literal between 1 and -1, you preceed the decimal with a 0; otherwise, you will get a compiler error (i.e. .1 + .1 does not work).

Syntax Example:
if (0.1 + 0.1 + 0.1) = 0.3 then
  ShowMessage('Correct')
else
  ShowMessage('Not correct');
 
//Complete example:
if x = true then
begin
  ShowMessage('x is true');
end
Else If y = 'Mike' Then 
  ShowMessage('hello mike')
Else 
  ShowMessage('last option');
C#:   if..else if..else

Use () around evaluation with no "then".

Syntax Example:
Boolean x = true;


if (x)
{
MessageBox.Show("hello");
}
else if (x==false)
{
MessageBox.Show("goodbye");
}
else
{
  MessageBox.Show("what?");
}





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