《编译原理》报告

1、精选优质文档-倾情为你奉上 SHANGHAI UNIVERSITY<编译原理>实验报告学 院计算机工程与科学学院组 号实验三日期2016.4.23学号姓名主要工作贡献因子一、实验目的与要求l 给出 PL/0 文法规范，要求编写 PL/0 语言的语法分析程序。l 通过设计、编制、调试一个典型的语法分析程序，实现对词法分析程序所提供的单词序列进行语法检查和结构分析，进一步掌握常用的语法分析方法。l 选择一种语法分析方法（递归子程序法、LL(1)分析法、算符优先分析法、SLR(1)分析法） ；选择常见程序语言都具备的语法结构，如赋值语句，特别是表达式，作为分析对象确定语法分析的方法。l

2、将实验二“词法分析”的输出结果，作为表达式语法分析器的输入，进行语法解析，对于语法正确的表达式，报告“语法正确” ；对于语法错误的表达式，报告“语法错误” ， 指出错误原因。l 源程序中字符不区分大小写，即： “a1”和“A1”是同一个标识符。l 准备至少 10 组测试用例， 每组测试用例包括： 输入文件和输出结果。二、 实验环境C+IDE：Codeblocks三、实验内容已给 PL/0 语言文法，构造表达式部分的语法分析器。分析对象算术表达式的 BNF 定义如下：<表达式> := +|-<项><加法运算符> <项><项> := &l

3、t;因子><乘法运算符> <因子><因子> := <标识符>|<无符号整数>| (<表达式>)<加法运算符> := +|-<乘法运算符> := *|/四、 实验内容的设计与实现源程序： #include<string>#include<cstring>#include<fstream>#include<stack>using namespace std;const string basic_word="begin","

4、;call","const","do","end","if","odd","procedure","read","then","var","while","write"const string basic_word_name="beginsym","callsym","constsym","dosy

5、m","endsym","ifsym","oddsym","proceduresym","readsym","thensym","varsym","whilesym","writesym"const string operator_="+-*/<>=:"/杩愮畻绗?const string operator_="+","-","

6、;*","/","=","#","<","<=",">",">=",":="const string operator_name="plus","minus","times","slash","eql","neq","lss","leq",&qu

7、ot;gtr","geq","becomes"const string cut_str="(),;. "const string cut_str_name="lparen","rparen","comma","semicolon","period","space"class compile private: string line;/瀛樺偍姣忎竴琛屾暟鎹? string buffer;/缂撳啿鍖? /int

8、 flag;/鏍囪瘑浣? /-1:鏃犲畾涔? /0:a-z A-Z /1:0-9 /2:+-*/<>=: /3:() ,;. /4:space,tab,n /5:闈?-4绫诲埆瀛楃 public: compile(string inname,string outname) ifstream fin(inname.c_str(),ios:in); fstream fout(outname.c_str(),ios:out); int flag=-1; if (fin.good() while (getline(fin, line)/鑾峰緱涓琛? int length=line.leng

9、th(); string t2="" string temp2; buffer="" for(int i=0;i<length;i+) flag=isWhat(linei); / cout<<linei<<endl; /cout<<buffer<<endl; temp2 =linei; /cout<<flag<<endl; if(i=length-1&&(flag=0|flag=1) string temp; temp=buffer; /cout<<

10、temp<<endl; buffer="" if(whatBasicWord(temp)!="no") fout<<"("<<whatBasicWord(temp)<<","<<temp<<")n" fout<<flush; cout<<"("<<whatBasicWord(temp)<<","<<temp<<&q

11、uot;)"<<endl; else if(isNumber(temp)=true) fout<<"("<<"number"<<","<<temp<<")n" fout<<flush; cout<<"("<<"number"<<","<<temp<<")"<<endl; e

12、lse if(markCheck(temp) fout<<"("<<"ident"<<","<<temp<<")n" fout<<flush; cout<<"("<<"ident"<<","<<temp<<")"<<endl; else fout<<"("<

13、<"illegal"<<","<<temp<<")n" fout<<flush; cout<<"("<<"illegal"<<","<<temp<<")"<<endl; else if(flag=0|flag=1|flag=5) buffer+=linei; /cout<<buffer<<endl; else

14、 string temp; temp=buffer; /cout<<temp<<endl; buffer="" if(temp!="") if(t2!="") if(t2=":") cout<<"(illegal,:)"<<endl; fout<<"(illegal,:)n" else cout<<"("<<whatOperator(t2)<<",&q

15、uot;<<t2<<")"<<endl; fout<<"("<<whatOperator(t2)<<","<<t2<<")n" t2="" fout<<flush; if(whatBasicWord(temp)!="no") fout<<"("<<whatBasicWord(temp)<<","

16、<<temp<<")n" fout<<flush; cout<<"("<<whatBasicWord(temp)<<","<<temp<<")"<<endl; else if(isNumber(temp)=true) fout<<"("<<"number"<<","<<temp<<"

17、;)n" fout<<flush; cout<<"("<<"number"<<","<<temp<<")"<<endl; else if(markCheck(temp) fout<<"("<<"ident"<<","<<temp<<")n" fout<<flush; cou

18、t<<"("<<"ident"<<","<<temp<<")"<<endl; else fout<<"("<<"illegal"<<","<<temp<<")n" fout<<flush; cout<<"("<<"illegal"&

19、lt;<","<<temp<<")"<<endl; if(flag=2) if(t2!="") if(t2=":"&&temp2!="=") cout<<"(illegal,:)"<<endl; fout<<"(illegal,:)n" fout<<flush; if(whatOperator(temp2)!="no") cout&

20、lt;<"("<<whatOperator(temp2)<<","<<temp2<<")"<<endl; fout<<"("<<whatOperator(temp2)<<","<<temp2<<")n" fout<<flush; else t2=temp2; else if(t2=">"|t2="<

21、"|t2=":")&&temp2="=") cout<<"("<<whatOperator(t2+temp2)<<","<<t2+temp2<<")"<<endl; fout<<"("<<whatOperator(t2+temp2)<<","<<t2+temp2<<")n" fou

22、t<<flush; t2="" else fout<<"("<<whatOperator(t2)<<","<<t2<<")n" fout<<flush; cout<<"("<<whatOperator(t2)<<","<<t2<<")"<<endl; cout<<"("&

23、lt;<whatOperator(temp2)<<","<<temp2<<")"<<endl; fout<<"("<<whatOperator(temp2)<<","<<temp2<<")n" fout<<flush; t2="" else if(temp2="<"|temp2=">"|temp2=&

24、quot;:") t2=temp2; else cout<<"("<<whatOperator(temp2)<<","<<temp2<<")"<<endl; fout<<"("<<whatOperator(temp2)<<","<<temp2<<")n" fout<<flush; else if(flag=3) /cout&

25、lt;<"33"<<temp2<<endl; cout<<"("<<whatCutStr(temp2)<<","<<temp2<<")"<<endl; fout<<"("<<whatCutStr(temp2)<<","<<temp2<<")n" fout<<flush; else if

26、(flag=4) else cout<<"can't open file"<<endl; int isWhat(char temp)/杩斿洖鏈瓧绗殑绫诲瀷 if(temp=' '|temp='t'|temp='n') return 4; if(isLetter(temp) return 0; if(isDigital(temp) return 1; if(isOperator_(temp) return 2; if(isCutStr(temp) return 3; return 5; strin

27、g whatCutStr(string temp) int i=0; for(i;i<cut_str.length();i+) if(temp0=cut_stri) return cut_str_namei; return "no" string whatBasicWord(string temp)/鍒柇鏄惁涓烘爣璇嗙 int i=0; int length=sizeof(basic_word)/sizeof(string); for(i;i<length;i+) if(isEqual(temp,basic_wordi) return basic_word_na

28、mei; return "no" string whatOperator(string temp) int length=sizeof(operator_)/sizeof(string); for(int i=0;i<length;i+) if(temp=operator_i) return operator_namei; return "no" bool isNumber(string temp) for(int i=0;i<temp.length();i+) if(!isDigital(tempi) return false; retur

29、n true; bool isOperator_(char temp)/鏄惁涓鸿繍绠楃 int i=0,length=operator_.length(); for(i;i<length;i+) if(temp=operator_i) break; if(i=length) return false; else return true; bool isCutStr(char temp)/鏄惁涓哄垎闅旂 int i=0,length=cut_str.length(); for(i;i<length;i+) if(temp=cut_stri) break; if(i=length) r

30、eturn false; else return true; bool isLetter(char temp)/鍒柇鏄惁涓哄瓧姣? if(temp>='a'&&temp<='z')|(temp>='A'&&temp<='Z') return true; return false; bool isDigital(char temp)/鍒柇鏄惁涓烘暟瀛? if(temp>='0'&&temp<='9') return t

31、rue; return false; bool markCheck(string tt)/鏍囪瘑绗悎娉曟鏌? if(tt0!='_'&&!isLetter(tt0) return false; else /cout<<tt<<endl; for(int i=1;i<tt.length();i+) if(!isLetter(tti)&&!isDigital(tti)&&tti!='_')/鍑虹幇 return false; return true; bool isEqual(string

32、 a1,string a2)/鍒柇涓釜瀛楃鏄惁鐩哥瓑 if(a1.length()!=a2.length() return false; else int length=a1.length(); for(int i=0;i<length;i+) if(a1i!=a2i&&a1i+32!=a2i&&a1i-32!=a2i) return false; return true; /* void writeInto(string filename)/鍐欏叆鏂囦欢 ofstream fout; fout.open(filename.c_str(); for(int

33、 i=0;i<len_;i+) fout<<"("<<indent_namei<<","<<indent_timesi<<")n" fout<<flush; fout.close(); */;class Grammarprotected: char state; int pre_k; bool flag; int index; string cate; string cate_str;public: Grammar() state='A' f

34、lag=1; pre_k=0; index=0; void setCate(string c,string c_str) cate=c; cate_str=c_str; void displayStatus() /cout<<pre_k<<endl; if(pre_k!=0) if(pre_k>0) cout<<"error:lost ')' to match '('. "<<endl; else cout<<"error:to more ')' at

35、 last."<<endl; if(flag=1&&(state='C'|state='D') cout<<"grammar legal!"<<endl; else if (flag=1&&(state!='C'|state!='D') cout<<"error:lost some expression at last!"<<endl; cout<<"grammar i

36、llegal!"<<endl; else cout<<"grammar illegal!"<<endl; void start(string inname) fstream fin(inname.c_str(),ios:in); string line,word,categrey,str; if(fin.good() while(getline(fin,line) int i=1; index+; categrey=""str="" word=line1; while(word!=&quo

37、t;,") categrey+=word; word=line+i; word=line+i; while(i!=line.length()-1) str+=word; word=line+i; /cout<<cate_str<<endl; cate=categrey; cate_str=str; if(cate_str="") break; inputStr(); else cout<<"can't open file"<<endl; void inputStr() if(state=&

38、#39;A') if(cate_str!="+"&&cate_str!="-"&&cate!="ident"&&cate!="number"&&cate_str!="(") cout<<"error:The begin of a expression must be '+' or '-' or '(' or 'ident' or '

39、number'.please check:"<<cate_str<<" ("<<index<<")"<<endl; flag=0; else if(cate_str="+"|cate_str="-") state='B' else if(cate="ident"|cate="number") state='B' inputStr(); else if(cate_str="(") pre_k+; else if(state='B') if(cate_str="(") state='A' pre_k+; else if(cate="ident"|cate="number") state='C&#