php代码
0, '(' => 10, '+' => 20, '-' => 20, '*' => 30, '/' => 30); //四则运算 private $_operator = array('(', '+', '-', '*', '/', ')'); public function __construct($expression) { $this->_init($expression); } private function _init($expression) { $this->_expression = $expression; } public function exp2rpn() { $len = strlen($this->_expression); for($i = 0; $i < $len; $i++) { $char = substr($this->_expression, $i, 1); if ($char == '(') { $this->_stack[] = $char; continue; } else if ( ! in_array($char, $this->_operator)) { $this->_rpnexp[] = $char; continue; } else if ($char == ')') { for($j = count($this->_stack); $j >= 0; $j--) { $tmp = array_pop($this->_stack); if ($tmp == "(") { break; } else { $this->_rpnexp[] = $tmp; } } continue; } else if ($this->_priority[$char] <= $this->_priority[end($this->_stack)]) { $this->_rpnexp[] = array_pop($this->_stack); $this->_stack[] = $char; continue; } else { $this->_stack[] = $char; continue; } } for($i = count($this->_stack); $i >= 0; $i--) { if (end($this->_stack) == '#') break; $this->_rpnexp[] = array_pop($this->_stack); } return $this->_rpnexp; } } //测试实例 $expression = "(A*(B+C)-E+F)*G"; var_dump($expression); $mathrpn = new math_rpn($expression); var_dump($mathrpn->exp2rpn()); /*End of php*/