E2030 Duplicate case label (Delphi)

Go Up to Error and Warning Messages (Delphi)

This error message occurs when there is more than one case label with a given value in a case statement.

program Produce;
function DigitCount(I: Integer): Integer;
begin
 case Abs(I) of
 0 DigitCount := 1;
 0 ..9 DigitCount := 1; (*<-- Error message here*)
 10 ..99 DigitCount := 2;
 100 ..999 DigitCount := 3;
 1000 ..9999 DigitCount := 4;
 10000 ..99999 DigitCount := 5;
 100000 ..999999 DigitCount := 6;
 1000000 ..9999999 DigitCount := 7;
 10000000 ..99999999 DigitCount := 8;
 100000000..999999999 DigitCount := 9;
 else DigitCount := 10;
 end;
end;
begin
 Writeln( DigitCount(12345) );
end.

Here we did not pay attention and mentioned the case label 0 twice.

program Solve;
function DigitCount(I: Integer): Integer;
begin
 case Abs(I) of
 0 ..9 DigitCount := 1;
 10 ..99 DigitCount := 2;
 100 ..999 DigitCount := 3;
 1000 ..9999 DigitCount := 4;
 10000 ..99999 DigitCount := 5;
 100000 ..999999 DigitCount := 6;
 1000000 ..9999999 DigitCount := 7;
 10000000 ..99999999 DigitCount := 8;
 100000000..999999999 DigitCount := 9;
 else DigitCount := 10;
 end;
end;
begin
 Writeln( DigitCount(12345) );
end.

In general, the problem might not be so easy to spot when you have symbolic constants and ranges of case labels - you might have to write down the real values of the constants to find out what is wrong.

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