编译原理实验报告LL1分析法

1、课 程 编译原理 实验名称 实验二 LL(1)分析法 实验目的1掌握LL(1)分析法的基本原理； 2掌握LL(1)分析表的构造方法； 3掌握LL(1)驱动程序的构造方法。一. 实验内容及要求根据某一文法编制调试LL（1）分析程序，以便对任意输入的符号串进行分析。本次实验的目的主要是加深对预测分析LL（1）分析法的理解。 对下列文法，用LL（1）分析法对任意输入的符号串进行分析：（1）E->TG（2）G->+TG（3）G->（4）T->FS（5）S->*FS（6）S->（7）F->(E)（8）F->i程序输入一以#结束的符号串(包括+*（）i#)，

2、如：i+i*i#。输出过程如下：步骤分析栈剩余输入串所用产生式1Ei+i*i#E->TG.二. 实验过程及结果代码如下：#include<iostream>#include "edge.h"using namespace std;edge:edge()cin>>left>>right;rlen=right.length();if(NODE.find(left)>NODE.length() NODE+=left;string edge:getlf()return left;string edge:getrg()return ri

3、ght;string edge:getfirst()return first;string edge:getfollow()return follow;string edge:getselect()return select;string edge:getro()string str;str+=right0;return str;int edge:getrlen()return right.length();void edge:newfirst(string w)int i;for(i=0;i<w.length();i+)if(first.find(wi)>first.length

4、()first+=wi;void edge:newfollow(string w)int i;for(i=0;i<w.length();i+)if(follow.find(wi)>follow.length()&&wi!='')follow+=wi;void edge:newselect(string w)int i;for(i=0;i<w.length();i+) if(select.find(wi)>select.length()&&wi!='')select+=wi;void edge:delfirs

5、t()int i=first.find('');first.erase(i,1);int SUM;string NODE,ENODE;/计算firstvoid first(edge ni,edge *n,int x)int i,j;for(j=0;j<SUM;j+)if(ni.getlf()=nj.getlf()if(NODE.find(nj.getro()<NODE.length() for(i=0;i<SUM;i+) if(ni.getlf()=nj.getro() first(ni,n,x);else nx.newfirst(nj.getro();/计算

6、followvoid follow(edge ni,edge *n,int x)int i,j,k,s;string str;for(i=0;i<ni.getrlen();i+)s=NODE.find(ni.getrg()i);if(s<NODE.length()&&s>-1) /是非终结符if(i<ni.getrlen()-1) /不在最右for(j=0;j<SUM;j+)if(nj.getlf().find(ni.getrg()i)=0)if(NODE.find(ni.getrg()i+1)<NODE.length()for(k=0;k&

7、lt;SUM;k+) if(nk.getlf().find(ni.getrg()i+1)=0) nj.newfollow(nk.getfirst(); if(nk.getfirst().find("")<nk.getfirst().length() nj.newfollow(ni.getfollow(); elsestr.erase();str+=ni.getrg()i+1;nj.newfollow(str);/计算selectvoid select(edge &ni,edge *n)int i,j;if(ENODE.find(ni.getro()<EN

8、ODE.length()ni.newselect(ni.getro();if(ni.getro()="")ni.newselect(ni.getfollow();elsefor(i=0;i<ni.getrlen();i+)for(j=0;j<SUM;j+)if(ni.getrg()i=nj.getlf()0)ni.newselect(nj.getfirst();if(nj.getfirst().find('')>nj.getfirst().length()return;/输出集合void out(string p)int i;if(p.le

9、ngth()=0) return;cout<<""for(i=0;i<p.length()-1;i+) cout<<pi<<","cout<<pi<<""/连续输出符号void outfu(int a,string c)int i;for(i=0;i<a;i+)cout<<c;/输出预测分析表void outgraph(edge *n,string (*yc)50)int i,j,k;bool flag;for(i=0;i<ENODE.lengt

10、h();i+) if(ENODEi!='') outfu(10," ");cout<<ENODEi; outfu(10," ");cout<<"#"<<endl;int x;for(i=0;i<NODE.length();i+)outfu(4," ");cout<<NODEi;outfu(5," ");for(k=0;k<ENODE.length();k+)flag=1;for(j=0;j<SUM;j+) if(N

11、ODEi=nj.getlf()0) x=nj.getselect().find(ENODEk); if(x<nj.getselect().length()&&x>-1) cout<<"->"<<nj.getrg(); ycik=nj.getrg(); outfu(9-nj.getrlen()," "); flag=0; x=nj.getselect().find('#'); if(k=ENODE.length()-1&&x<nj.getselect().len

12、gth()&&x>-1) cout<<"->"<<nj.getrg(); ycij=nj.getrg(); if(flag&&ENODEk!='') outfu(11," ");cout<<endl;/分析符号串int pipei(string &chuan,string &fenxi,string (*yc)50,int &b)char ch,a;int x,i,j,k;b+;cout<<endl<<"

13、; "<<b;if(b>9) outfu(8," ");else outfu(9," ");cout<<fenxi;outfu(26-chuan.length()-fenxi.length()," ");cout<<chuan;outfu(10," ");a=chuan0;ch=fenxifenxi.length()-1;x=ENODE.find(ch);if(x<ENODE.length()&&x>-1) if(ch=a) fenxi

14、.erase(fenxi.length()-1,1);chuan.erase(0,1);cout<<"'"<<a<<"'匹配"if(pipei(chuan,fenxi,yc,b) return 1;else return 0; elsereturn 0;else if(ch='#') if(ch=a) cout<<"分析成功"<<endl; return 1;elsereturn 0; elseif(ch='') fenxi.e

15、rase(fenxi.length()-1,1); if(pipei(chuan,fenxi,yc,b) return 1; else return 0;else i=NODE.find(ch); if(a='#') x=ENODE.find(''); if(x<ENODE.length()&&x>-1) j=ENODE.length()-1; else j=ENODE.length(); elsej=ENODE.find(a); if(ycij.length() cout<<NODEi<<"->

16、;"<<ycij; fenxi.erase(fenxi.length()-1,1); for(k=ycij.length()-1;k>-1;k-) if(ycijk!='')fenxi+=ycijk; if(pipei(chuan,fenxi,yc,b) return 1; else return 0; elsereturn 0;void main()edge *n;string str,(*yc)50;int i,j,k;bool flag=0;cout<<"请输入上下文无关文法的总规则数："<<endl

17、;cin>>SUM;cout<<"请输入具体规则（格式：左部 右部，为空）："<<endl;n=new edgeSUM;for(i=0;i<SUM;i+) for(j=0;j<ni.getrlen();j+) str=ni.getrg();if(NODE.find(strj)>NODE.length()&&ENODE.find(strj)>ENODE.length()ENODE+=strj; /计算first集合for(i=0;i<SUM;i+) first(ni,n,i);/outfu(10

18、,"*");cout<<endl;for(i=0;i<SUM;i+) if(ni.getfirst().find("")<ni.getfirst().length() if(NODE.find(ni.getro()<NODE.length() for(k=1;k<ni.getrlen();k+) if(NODE.find(ni.getrg()k)<NODE.length() for(j=0;j<SUM;j+) if(ni.getrg()k=nj.getlf()0) ni.newfirst(nj.getfir

19、st(); break; if(nj.getfirst().find("")>nj.getfirst().length() ni.delfirst();break; /计算follow集合for(k=0;k<SUM;k+) for(i=0;i<SUM;i+) if(ni.getlf()=n0.getlf() ni.newfollow("#");follow(ni,n,i); for(i=0;i<SUM;i+) for(j=0;j<SUM;j+) if(nj.getrg().find(ni.getlf()=nj.getrlen

20、()-1) ni.newfollow(nj.getfollow(); /计算select集合for(i=0;i<SUM;i+) select(ni,n);for(i=0;i<NODE.length();i+) str.erase(); for(j=0;j<SUM;j+)if(nj.getlf()0=NODEi)if(!str.length()str=nj.getselect();elsefor(k=0;k<nj.getselect().length();k+)if(str.find(nj.getselect()k)<str.length()flag=1;break

21、;/输出cout<<endl<<"非终结符"outfu(SUM," ");cout<<"First"outfu(SUM," ");cout<<"Follow"<<endl;outfu(5+SUM,"-*-");cout<<endl;for(i=0;i<NODE.length();i+) for(j=0;j<SUM;j+)if(NODEi=nj.getlf()0) outfu(3,"

22、"); cout<<NODEi; outfu(SUM+4," "); out(nj.getfirst(); outfu(SUM+4-2*nj.getfirst().length()," "); out(nj.getfollow(); cout<<endl; break;outfu(5+SUM,"-*-");cout<<endl<<"判定结论： "if(flag) cout<<"该文法不是LL(1)文法!"<<endl; return;else cout<<"该文法是LL(1)文法!"<<endl;/输出预测分析表cout<<endl<<"预测分析表如下：