46 lines
1.3 KiB
PHP
46 lines
1.3 KiB
PHP
<?php
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function rpn($postFix){
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$stack = Array();
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echo "Input\tOperation\tStack\tafter\n" ;
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$token = explode(" ", trim($postFix));
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$count = count($token);
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for($i = 0 ; $i<$count;$i++)
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{
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echo $token[$i] ." \t";
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$tokenNum = "";
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if (is_numeric($token[$i])) {
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echo "Push";
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array_push($stack,$token[$i]);
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}
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else
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{
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echo "Operate";
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$secondOperand = end($stack);
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array_pop($stack);
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$firstOperand = end($stack);
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array_pop($stack);
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if ($token[$i] == "*")
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array_push($stack,$firstOperand * $secondOperand);
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else if ($token[$i] == "/")
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array_push($stack,$firstOperand / $secondOperand);
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else if ($token[$i] == "-")
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array_push($stack,$firstOperand - $secondOperand);
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else if ($token[$i] == "+")
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array_push($stack,$firstOperand + $secondOperand);
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else if ($token[$i] == "^")
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array_push($stack,pow($firstOperand,$secondOperand));
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else {
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die("Error");
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}
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}
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echo "\t\t" . implode(" ", $stack) . "\n";
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}
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return end($stack);
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}
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echo "Compute Value: " . rpn("3 4 2 * 1 5 - 2 3 ^ ^ / + ");
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?>
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