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<title>True or False</title>
<body bgcolor="#ffffcc">
<hr>
<center>
<h1>True or False.</h1>
</center>
<hr>
The concept of an <a href="../CONCEPT/expressions.html">expression</a> evaluating to true or false is one of
the corner stones of C. BUT the language derives true and false in an
unusual way.<p>
Basicly there is no boolean value. The number 0 is considered to be false
and all other numbers are considered to be true....<p>
Please consider the following expressions.
<pre>
(1 == 1) true
(1 != 1) false
(i = 1) true
(i = 0) false
(i = 1 + 1) true
</pre>
The first two examples should be clear but the last ones need explanation .<p>
The last three examples assign a value to a variable and a side effect of
assignment is to return the value assigned, it is <b>this</b> value that is tested
to be true or false.<p>
Looking at the last example:
<pre>
(i = 1 + 1)
(i = 2)
(2)
</pre>
<ul>
<li>The third expression assigns a value of 1 to <b>i</b>. 1 is considered to
be true because it is non-zero.
<p>
<li>The fourth expression assigns a value of 0 to <b>i</b>. 0 is considered to
be false.
<p>
<li>The fith expression assigns a value of 2 to <b>i</b>. 2 is considered to
be true, because it is non-zero.
</ul>
<p>
<hr>
<h2>See Also:</h2>
<img src=../../GRAPHICS/whiteball.gif>
<A HREF="../SYNTAX/enum.html">enum keyword</A>
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<address>Martin Leslie
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</address> Corrections made by Christopher Wolf
<! cwolf@tools.micro.ti.com>
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