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In the case of programs run under DOS, the exit() status can be accessed via the errorlevel parameter in the DOS if command - though this is normally only used in batch files.

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In general, the terms character and byte can be regarded as almost synonymous here.

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When running a program under MS-Windows, this corresponds to the MS-DOS window within which the program is being run.

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Incidentally, when input is being taken from the keyboard, under DOS, the special key combination CTRL-Z, followed by Enter, is normally used to signal end of file.

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y is always of type double; but it can have an integer value, e.g. 4.0.