Switch in Pascal

Here’s the translation into Pascal:

Switch statements express conditionals across many branches.

Here’s a basic switch.

program SwitchExample;

uses SysUtils;

begin
    var i: Integer := 2;
    Write('Write ', i, ' as ');
    case i of
        1: Writeln('one');
        2: Writeln('two');
        3: Writeln('three');
    end;

You can use commas to separate multiple expressions in the same case statement. We use the optional default case in this example as well.

    case DayOfTheWeek(Now) of
        6, 7: Writeln('It's the weekend');
        else Writeln('It's a weekday');
    end;

switch without an expression is an alternate way to express if/else logic. Here we also show how the case expressions can be non-constants.

    var t: TDateTime := Now;
    case True of
        t.Hour < 12: Writeln('It's before noon');
        else Writeln('It's after noon');
    end;

A type switch compares types instead of values. You can use this to discover the type of an interface value. In this example, the variable t will have the type corresponding to its clause.

    procedure whatAmI(v: Variant);
    begin
        case VarType(v) of
            varBoolean: Writeln('I\'m a bool');
            varInteger: Writeln('I\'m an int');
            else Writeln('Don\'t know type ', VarType(v));
        end;
    end;

    whatAmI(True);
    whatAmI(1);
    whatAmI('hey');
end.

To run the program, compile the code using a Pascal compiler (like Free Pascal Compiler) and execute the binary.

$ fpc SwitchExample.pas
$ ./SwitchExample
Write 2 as two
It's a weekday
It's after noon
I'm a bool
I'm an int
Don't know type 258

Next example: Arrays.

If Else in Pascal

Arrays in Pascal

Learn X By Example

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Switch in Pascal