Switch

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Description

The Switch statement allows the user to set up a series of Cases and a Default, one of which will be executed, depending on the value of an input argument. For more information, see Flow Control Script Reference.

 

 

Syntax

 

// Variable Switch

Variable a;

Switch (a);

    Case 0:

          // Do something

          Break;

    Case 1:

          // Fall through to next block

    Default:

          // Do something

          Break;

End;

 

// String Switch

String b;

Switch (b);

    Case "yes":

          // Do something

          Break;

    Case "no":

          // Fall through to next block

    Default:

          // Do something

          Break;

End;

 

 

Details

•The "Case" must be a literal number or string and must evaluate to an integer. Variable or String objects cannot be used, to prevent conflicts in which the evaluation of the Case changes the value of the Variable or String in question.

•If the Switch input argument evaluates to one of the cases, that Case is executed.

•If the Switch input argument does not evaluate to any of the Cases, the Default is executed.

•A Break statement stops the evaluation of all following Cases (including the Default) and exits the Switch block entirely.

•Note that a colon (:) is used after each Case and Default statement, instead of a semicolon (;).

•The Break statement can also be used to exit a While or a For loop without completing any remaining iterations of the loop or executing any remaining commands within the loop.

 

Examples

Use Switch to determine what type of output will be generated

Ephemeris Ephemeris1;      

 

// User sets a:

Variable a = 1;

           

While (Spacecraft1.ElapsedTime < TIMESPAN(1 days));

 

    // Determine output type

    Switch (a);

          Case 0:

                // Do nothing

                Break;

          Case 1:

                Plot Spacecraft1.ElapsedTime, Spacecraft1.A;

                Break;

          Case 2:

                Report Spacecraft1.ElapsedTime, Spacecraft1.A;

                Break;

          Case 3:

                Put Spacecraft1 to Ephemeris1;

                Break;

          Default:

                Watch Spacecraft1.A;

                Break;

    End;

 

    View Spacecraft1;

    Step Spacecraft1;

End;

 

Use Switch to determine whether to generate output Ephemeris file

Switch (a);

    Case 3:

          Put Ephemeris1 to FFephem "SwitchEphem.FFephem";

          Break;

    Default:

          // Do nothing

          Break;

End;

 

Use Switch to maneuver a Spacecraft

// Create Burn

ImpulsiveBurn ImpulsiveBurn1;

ImpulsiveBurn1.AttitudeSystem = 1;

ImpulsiveBurn1.BurnDirection[0] = 0.1;

 

 

// Propagate and Maneuver Spacecraft

While (Spacecraft1.ElapsedTime < 1);

 

    Switch (Spacecraft1.ElapsedTime.ToHours());

 

          Case 1:

                Maneuver Spacecraft1 using ImpulsiveBurn1;

                Step Spacecraft1;

                Break;

 

          Case 3:

                Maneuver Spacecraft1 using ImpulsiveBurn1;

                Step Spacecraft1;

                Break;

 

          Case 4:

                  // Fall through to next block

 

          Default:

                Step Spacecraft1;

                Break;

    End;

End;

 

 

See Also

•If Statement