1 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 2 <html xmlns="http://www.w3.org/1999/xhtml"> 3 <head> 4 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> 5 <title> 计算器 </title> 6 <meta name="keywords" content="" /> 7 <meta name="description" content="" /> 8 </head> 9 10 <body> 11 <form> 12 请输入一个表达式：<input type="text" name="exp" value="<?php echo $_GET['exp']; ?>"> 13 <input type="submit" value="计算"> 14 </br> 15 </form> 16 <?php 17 $input = $_GET['exp']; 18 echo $input.'='; 19 echo '<hr/>'; 20 $strStark = new myStark(); 21 $numStark = new myStark(); 22 for($i =0;$i<strlen($input);$i++){ 23 //逐行遍历 24 if(!isOper($input[$i])){ 25 //数值入数栈 26 if($i>0 && $isNum){ 27 $numStark->push($numStark->pop().$input[$i]); 28 }else{ 29 $numStark->push($input[$i]); 30 } 31 $isNum = true; //标志为数 32 }else{ 33 $isNum = false; //标志为非数 34 while($strStark->isEmpty() && oper($strStark->getTop()) >= oper($input[$i])){ 35 $num1 = $numStark->pop(); 36 $num2 = $numStark->pop(); 37 $oper = $strStark->pop(); 38 $res = pay($num1,$oper,$num2); 39 $numStark->push($res); 40 } 41 $strStark->push($input[$i]); 42 } 43 } 44 while($strStark->isEmpty()){ 45 $num1 = $numStark->pop(); 46 $num2 = $numStark->pop(); 47 $oper = $strStark->pop(); 48 $res = pay($num1,$oper,$num2); 49 $numStark->push($res); 50 } 51 echo $numStark->stark[$numStark->top]; 52 ?> 53 </body> 54 </html> 55 56 <?php 57 function isOper($str){ 58 if(in_array($str,array('+','-','*','/','(',')','[',']','{','}'))){ 59 return true; 60 }else{ 61 return false; 62 } 63 } 64 function oper($str){ 65 switch($str){ 66 case '+':case '-': 67 $oper = 1; 68 break; 69 case '*':case '/': 70 $oper = 2; 71 break; 72 } 73 return $oper; 74 } 75 function pay($x,$str,$y){ 76 switch($str){ 77 case '+':$return = $x+$y;break; 78 case '-':$return = $y-$x;break; 79 case '*':$return = $x*$y;break; 80 case '/':$return = $y/$x;break; 81 } 82 return $return; 83 } 84 class myStark{ 85 public $top = -1; 86 public $maxStark = 5; 87 public $stark = array(); 88 public function isEmpty(){ 89 if($this->top == -1){ 90 return false; 91 }else{ 92 return true; 93 } 94 } 95 /*栈顶*/ 96 public function getTop(){ 97 return $this->stark[$this->top]; 98 } 99 /*入栈*/ 100 public function push($val){ 101 if($this->top > $this->maxStark - 1){ 102 return false; 103 } 104 $this->top ++; 105 $this->stark[$this->top] = $val; 106 } 107 /*出栈*/ 108 public function pop(){ 109 if($this->top <= -1){ 110 return false; 111 } 112 $return = $this->stark[$this->top]; 113 $this->top -- ; 114 return $return; 115 } 116 /*打印*/ 117 public function show(){ 118 for($i = $this->top;$i>-1;$i--){ 119 echo 'stack['.$i.']='.$this->stark[$i].'<br />'; 120 } 121 } 122 } 123 124 ?>
源代码下载：Calculator_1205.zip