43 lines
1.0 KiB
Plaintext
43 lines
1.0 KiB
Plaintext
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{ Copyright (c) 1988, 1989 by Borland International, Inc. }
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{$F+}
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program ProcVar;
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{ For an extensive discussion of procedural types, variables and
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parameters, refer to Chapter 8 in the Turbo Pascal Reference
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Guide (or Chapter 7 in the Turbo Pascal 5.0 Update manual).
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}
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type
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IntFuncType = function (x, y : integer) : integer; { No func. identifier }
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var
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IntFuncVar : IntFuncType;
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procedure DoSomething(Func : IntFuncType; x, y : integer);
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begin
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Writeln(Func(x, y):5); { call the function parameter }
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end;
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function AddEm(x, y : integer) : integer;
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begin
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AddEm := x + y;
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end;
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function SubEm(x, y : integer) : integer;
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begin
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SubEm := x - y;
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end;
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begin
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{ Directly: }
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DoSomething(AddEm, 1, 2);
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DoSomething(SubEm, 1, 2);
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{ Indirectly: }
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IntFuncVar := AddEm; { an assignment, not a call }
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DoSomething(IntFuncVar, 3, 4); { a call }
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IntFuncVar := SubEm; { an assignment, not a call }
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DoSomething(IntFuncVar, 3, 4); { a call }
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end.
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