90 lines
3.0 KiB
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90 lines
3.0 KiB
HTML
<HTML>
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<HEAD><TITLE>QuickBASIC 3.0 - Long Entry</TITLE></HEAD>
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<A HREF="info.html">[About The Guide]</A>
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<PRE>
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<B>IF Conditional Branch</B>
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1. Block syntax
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<B>IF</B> <U>expression</U> <B>THEN</B>
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<U>statement1</U>
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[<U>statement2</U>]
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.
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.
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.
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[ELSEIF <U>expression</U> THEN
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<U>statement10</U>
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[<U>statement11</U>]
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.
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.
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.
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[ELSE
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<U>statement15</U>
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[<U>statement16</U>]]
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.
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.
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.
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<B>ENDIF</B>
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2. Single-line syntax (three variants)
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<B>IF</B> <U>expression</U> <B>THEN</B> <U>statement1</U> [ELSE <U>statement2</U>]
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Causes QuickBASIC to make a decision based on the value of an
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expression.
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<U>expression</U> A numeric expression; 0 is equivalent to FALSE, while all
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other values are equivalent to TRUE.
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<U>statement</U> Any legal statement. The single-line mode's statement can
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be just a line number or line label. This is equivalent
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to a GOTO statement with the specified label.
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----------------------------------------------------------------------
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<B>Notes:</B> Each <U>expression</U> in the IF/ELSEIF construct is tested in
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order. As soon as an <U>expression</U> is found to be TRUE, then
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its corresponding statements are executed. If no
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expressions are TRUE, then the statements following the
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ELSE keyword are executed. If ELSE is not specified, then
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execution continues with the statement following the ENDIF
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or the single-line IF statement.
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The only difference between QuickBASIC's one-line
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construct and that of interpreted BASIC is that QuickBASIC
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allows the use of labels as well as numbered lines.
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In the block construct, the following rules apply:
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IF, ELSE, ELSEIF, and ENDIF must all be the first
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keywords on their respective lines.
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THEN must be the last keyword on its line; if anything
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other than a comment follows on the same line with
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THEN, QuickBASIC thinks it's reading a single-line
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IF/THEN/ELSE construct.
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IF blocks may be nested.
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Do not put a colon before the ELSE keyword.
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</PRE>
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<HR>
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<B>See Also:</B>
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<A HREF="ng209fe.html">ON...GOTO</A>
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<A HREF="ng20631.html">ON...GOSUB</A>
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<A HREF="ng2d400.html">SELECT</A>
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<HR>
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This page created by ng2html v1.05, the Norton guide to HTML conversion utility.
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Written by <A HREF="http://www.acemake.com/hagbard">Dave Pearson</A>
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