SDUT-编译原理-小codeblocks

 1 #include<bits/stdc++.h>
 2 #include<list>
 3 using namespace std;
 4 string str;
 5 char line;
 6 string num;
 7 string s;
 8 int flag =0;
 9 
10 string key[]= {"main","if","else","for","while","int"};
11 
12 int main()
13 {
14     while(cin.get(line))
15     {
16         str+=line;
17     }
18     for(int i=0; i<=str.size(); i++)
19     {
20         //运算符： = + - * / < <= > >= == !=
21         //判断加减乘除
22         if(str[i]=='+'||str[i]=='-'||str[i]=='*'||str[i]=='/')
23             cout<<'('<<"operator"<<","<<str[i]<<')'<<endl;
24         //判断比较符
25         if(str[i]=='='||str[i]=='>'||str[i]=='<'||str[i]=='!')
26         {
27             if(str[i+1]=='=')
28             {
29                 cout<<'('<<"operator"<<","<<str[i]<<str[i+1]<<')'<<endl;
30                 i++;
31             }
32             else
33                 cout<<'('<<"operator"<<","<<str[i]<<')'<<endl;
34         }
35         //界符boundary  { } ( ) , ;
36         if(str[i]=='{'||str[i]=='}'||str[i]=='('||str[i]==')'||str[i]==','||str[i]==';')
37         {
38             cout<<'('<<"boundary"<<","<<str[i]<<')'<<endl;
39         }
40         //判断整数
41         if(str[i]>='0'&&str[i]<='9')
42         {
43             while(str[i]>='0'&&str[i]<='9')
44             {
45                 num+=str[i];
46                 i++;
47             }
48             i--;
49             cout<<'('<<"integer"<<","<<num<<')'<<endl;
50             num="";
51         }
52         //当以字母开头
53         if((str[i]<='Z'&&str[i]>='A')||(str[i]<='z'&&str[i]>='a'))
54         {
55             while((str[i]<='Z'&&str[i]>='A')||(str[i]<='z'&&str[i]>='a')||(str[i]<='9'&&str[i]>='0'))
56             {
57                 s+=str[i];
58                 i++;
59             }
60             for(int j=0; j<=5; j++)
61             {
62                 if(key[j]==s)//判断是否是关键字
63                 {
64                     flag =1;
65                 }
66             }
67             if(flag==1)
68                 cout<<'('<<"keyword"<<","<<s<<')'<<endl;
69             else if(flag==0)
70                 cout<<'('<<"identifier"<<","<<s<<')'<<endl;
71             s="";
72             i--;
73             flag=0;
74         }
75     }
76 }