软件工程作业二

 四则运算

public void createBTree(){  
 6             TreeNode lchild = null, rchild = null, lnode, rnode;  
 7               
 8             if(num == 1){  
 9                 lchild = new TreeNode(String.valueOf(Ran.getNumber(Arithmetic.getLine())), null, null);  
10                 rchild = new TreeNode(String.valueOf(Ran.getNumber(Arithmetic.getLine())), null, null);  
11                 root = new TreeNode(String.valueOf(Ran.getOperator()), lchild, rchild); 
12             }  
13             else{  
14                 int num1 = 0;  
15                 int n = getDeep() - 3;  
16                 boolean[] place = Ran.getChildPlace(num);  
17                 root = new TreeNode(String.valueOf(Ran.getOperator()), null, null);  
18                 opeList.add(root);  
19                   
20                 for(int i = 0; i < n; i++){  
21                     for(int j = 0; j < (int)Math.pow(2, i); j++, num1++){  
22                         lchild = new TreeNode(String.valueOf(Ran.getOperator()), null, null);  
23                         rchild = new TreeNode(String.valueOf(Ran.getOperator()), null, null);  
24                         opeList.get(j + num1).setChild(lchild, rchild);  
25                         opeList.add(lchild);  
26                         opeList.add(rchild);  
27                     }  
28                 }  
29                   
30                 for(int i = 0; i < place.length; i++){  
31                     if(place[i]){  
32                         lnode  = new TreeNode(String.valueOf(Ran.getNumber(Arithmetic.getLine())), null, null);  
33                         rnode  = new TreeNode(String.valueOf(Ran.getNumber(Arithmetic.getLine())), null, null);  
34                         if(i%2 == 0){  
35                             lchild = new TreeNode(String.valueOf(Ran.getOperator()), lnode, rnode);  
36                             opeList.add(lchild);  
37                             opeList.get(num1).setLchild(lchild);  
38                         }  
39                         else{  
40                             rchild = new TreeNode(String.valueOf(Ran.getOperator()), lnode, rnode);  
41                             opeList.add(rchild);  
42                             opeList.get(num1).setRchild(rchild);  
43                         }  
44                     }  
45                     else{  
46                         if(i%2 == 0){  
47                             lchild = new TreeNode(String.valueOf(Ran.getNumber(Arithmetic.getLine())), null, null);  
48                             opeList.get(num1).setLchild(lchild);  
49                         }  
50                         else{  
51                             rchild = new TreeNode(String.valueOf(Ran.getNumber(Arithmetic.getLine())), null, null);  
52                             opeList.get(num1).setRchild(rchild);  
53                         }  
54                     }  
55                     num1 = num1 + i%2;  
56                 }          
57             }  
58         }

括号添加及去掉：

 1   /** 
 2      * 先对每个运算式添加括号，然后根据去括号法则，去掉多余的子式的括号 
 3      *  
 4      * @return string 
 5      */  
 6     public String toString(){  
 7         String Lstr = "", Rstr = "", Str = "";  
 8         if(hasChild()){  
 9             if(getRchild().hasChild()){                           
10                 if(str.equals("÷")){  
11                     Rstr = getRchild().toString();                
12                 }  
13                 else if(str.equals("×") || str.equals("-")){  
14                     if(getRchild().str.equals("+") || getRchild().str.equals("-")){   
15                         Rstr = getRchild().toString();            
16                     }  
17                     else{  
18                         Rstr = getRchild().toString().substring(1, getRchild().toString().length()-1);    
19                     }  
20                 }  
21                 else{   
22                     Rstr = getRchild().toString().substring(1, getRchild().toString().length()-1);        
23                 }  
24             }  
25             else{  
26                 Rstr = getRchild().str;  
27             }  
28             //左子树的情况同右子树类似  
29             if(getLchild().hasChild()){                                               
30                 if(str.equals("×") || str.equals("÷")){  
31                     if(getLchild().str.equals("+") || getLchild().str.equals("-")){  
32                         Lstr = getLchild().toString();  
33                     }  
34                     else{  
35                         Lstr = getLchild().toString().substring(1, getLchild().toString().length()-1);  
36                     }  
37                 }  
38                 else{  
39                     Lstr = getLchild().toString().substring(1, getLchild().toString().length()-1);  
40                 }  
41             }  
42             else{  
43                 Lstr = getLchild().str;  
44             }  
45             Str = "(" + Lstr + str + Rstr + ")";                                      
46         }  
47         else{  
48             Str = str;  
49         }  
50         return Str;  
51     }

结果计算：

 1 /** 
 2      * 获取每个节点的运算结果，并检验除法 
 3      *  
 4      * @return result 
 5      */  
 6     public String getResult(){  
 7         if(hasChild()){  
 8             switch(str){  
 9                 case "+":  
10                     return String.valueOf(Integer.parseInt(getLchild().getResult()) + Integer.parseInt(getRchild().getResult()));  
11                 case "-":  
12                     if(Integer.parseInt(getLchild().getResult()) - Integer.parseInt(getRchild().getResult()) < 0) {
13                             setChild(getRchild(), getLchild()); //如果减法运算结果为负数，则只需要将左右孩子交换一下就行了
14                     }
15                     return String.valueOf(Integer.parseInt(getLchild().getResult()) - Integer.parseInt(getRchild().getResult()));  
16                 case "×":  
17                     return String.valueOf(Integer.parseInt(getLchild().getResult()) * Integer.parseInt(getRchild().getResult()));  
18                 case "÷":  
19                     if(getRchild().getResult().equals("0")){  //除数是0的情况
20                         while(str.equals("÷")){  
21                             str = String.valueOf(Ran.getOperator());  //重新生成运算符
22                         }  
23                         return this.getResult();  
24                     }  
25                     else if(Integer.parseInt(getLchild().getResult()) % Integer.parseInt(getRchild().getResult()) != 0){  
26                          while(str.equals("÷")){  
27                              str = String.valueOf(Ran.getOperator());  //重新生成运算符
28                          }  
29                         return this.getResult();  
30                     }  
31                     else  
32                         return String.valueOf(Integer.parseInt(getLchild().getResult()) / Integer.parseInt(getRchild().getResult()));  
33             }  
34         }   
35         return str;  
36     }