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<pre>
<code style="font-family: Courier New, Courier, monospace; font-size: 12">
~/tcltk$ <b>cat maths.tcl</b>
#!/usr/bin/tclsh
#
# Demonstrate operators and
# math functions
 
set PI [expr 2 * asin(1.0)]
 
if {$argc == 3} {
  set X [lindex $argv 0]
  set Y [lindex $argv 1]
  set Rad [lindex $argv 2]
 
  set Dist [expr sqrt(($X*$X)+($Y*$Y))]
  set Cir [expr 2*$PI*$Rad]
  set Area [expr $PI*$Rad*$Rad]
 
  puts stdout "Distance = $Dist"
  puts stdout "Circumference = $Cir"
  puts stdout "Area = $Area"
 
} else {
  puts stdout "Wrong argument count!"
  puts stdout "Needs X, Y, and Radius"
}

********
~/tcltk$ <b>./maths.tcl 3 4 5</b>
Distance = 5.0
Circumference = 31.4159265359
Area = 78.5398163397
			</code>
</pre>
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<td width="90%"><font size="4" face="Verdana, Arial, Helvetica"><b>Tcl operators and mathematical functions</b></font></td><td width="200" align="right"><font size="1" face="Verdana, Arial, Helvetica"><nobr>   第 4 页（共15 页）</nobr></font></td>
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<font size="2" face="Verdana, Arial, Helvetica">
<p>Tcl supports a standard array of operators and mathematical 
				functions. The operators include arithmetic, bitwise, and logical 
				operators, which are evaluated via the <i>expr</i> command using 
				common operator precedence rules. Also, considering Tcl's 
				fundamental roots as a string-oriented scripting language, there's 
				a reasonable complement of mathematical functions as follows:</p>
<p>
<ul>
<li>Trigonometric functions include cos(x), acos(x), cosh(x), 
					sin(x), asin(x), sinh(x), tan(x), atan(x), atan2(y, x), tanh(x),  
					and hypot(x, y). The pertinent unit for these functions is 
					radians.</li>
<li>The Log functions are exp(x), log(x), and log10(x).</li>
<li>The Arithmetic functions are ceil(x), floor(x), 
					fmod(x, y), pow(x, y), abs(x), int(x), double(x), and round(x).</li>
<li>Random numbers are handled by rand() and srand(x).</li>
</ul>
</p>
<p>The example at left makes use of just a few of these operators and 
				functions to calculate the distance between a specified point and 
				the origin, and  to return the circumference and area of a circle 
				of the specified radius. Additionally, in this example we use the 
				list index (<i>lindex</i>) command to access individual elements of 
				$argv.</p>
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