25 lines
546 B
PHP
25 lines
546 B
PHP
<?php
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// RPN Calculator
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//
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// Nigel Galloway - April 3rd., 2012
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//
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$WSb = '(?:^|\s+)';
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$WSa = '(?:\s+|$)';
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$num = '([+-]?(?:\.\d+|\d+(?:\.\d*)?))';
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$op = '([-+*\/^])';
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function myE($m) {
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return $m[3] == '^' ? ' ' . pow($m[1], $m[2]) . ' ' : ' ' . eval("return " . $m[1] . $m[3] . $m[2] . ";") . ' ';
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}
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while (!feof(STDIN)) {
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$s = trim(fgets(STDIN));
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if ($s == '')
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continue;
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do {
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$s = preg_replace_callback("/$WSb$num\\s+$num\\s+$op$WSa/", "myE", $s, -1, $n);
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} while ($n);
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echo floatval($s) . "\n";
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}
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?>
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