编译原理试验报告LL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-s(4) T-FS(5) S-*FS(6) S-(7) F-(E)(8) F-i程序输入一以#吉束的符号串(包括+*()i#),如：i+i*i#。输出过程如下：步骤分析栈剩余输入串所

2、用产生式1 Ei+i*i#E-TG.实验过程及结果代码如下：#include#includeedge.husingnamespacestd;edge:edge()cinleftright;rlen=right.length();if(NODE.find(left)NODE.length()NODE+=le化stringedge:getlf()returnleft;stringedge:getrg()returnright;stringedge:getfirst()(returnfirst;)stringedge:getfollow()(returnfollow;)stringedge:gets

3、elect()(returnselect;)stringedge:getro()(stringstr;str+=right0;returnstr;)intedge:getrlen()(returnright.length();)voidedge:newfirst(stringw)(inti;for(i=0;ifirst.length()first+=wi;)voidedge:newfollow(stringw)(inti;for(i=0;ifollow.length()&wi!=)follow+=wi;)voidedge:newselect(stringw)(inti;for(i=0;isel

4、ect.length()&wi!=)select+=wi;)inti=first.find();first.erase(i,1);)intSUM;stringNODE,ENODE;/计算firstvoidfirst(edgeni,edge*n,intx)(inti,j;for(j=0;jSUM;j+)(if(ni.getlf()=nj.getlf()(if(NODE.find(nj.getro()NODE.length()(for(i=0;iSUM;i+)if(ni.getlf()=nj.getro()first(ni,n,x);)elsenx.newfirst(nj.getro();)/计算

5、followvoidfollow(edgeni,edge*n,intx)(inti,j,k,s;stringstr;for(i=0;ini.getrlen();i+)(s=NODE.find(ni.getrg()i);if(s-1)是非终结符if(ini.getrlen()-1)/不在最右for(j=0;jSUM;j+)if(nj.getlf().find(ni.getrg()i)=0)(if(NODE.find(ni.getrg()i+1)NODE.length()(for(k=0;kSUM;k+)if(nk.getlf().find(ni.getrg()i+1)=0)(nj.newfoll

6、ow(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selectvoidselect(edge&ni,edge*n)inti,j;if(ENODE.find(ni.getro()ENODE.length()ni.newselect(ni.getro();if(ni.getro()=)ni.newselect(ni.getfollow();elsefor(i=0

7、;ini.getrlen();i+)for(j=0;jnj.getfirst().length()return;输出集合voidout(stringp)inti;if(p.length()=0)return;cout;for(i=0;ip.length()-1;i+)coutpi;)/连续输出符号voidoutfu(inta,stringc)(inti;for(i=0;ia;i+)coutc;输出预测分析表voidoutgraph(edge*n,string(*yc)50)(inti,j,k;boolflag;for(i=0;iENODE.length();i+)(if(ENODEi!=)(o

8、utfu(10,);coutENODEi;outfu(10,);cout#endl;intx;for(i=0;iNODE.length();i+)(outfu(4,);coutNODEi;outfu(5,);for(k=0;kENODE.length();k+)(flag=1;for(j=0;jSUM;j+)(if(NODEi=nj.getlf()0)(x=nj.getselect().find(ENODEk);if(x-1)(coutnj.getrg();ycik=nj.getrg();outfu(9-nj.getrlen(),);flag=0;)x=nj.getselect().find(

9、#);if(k=ENODE.length()-1&x-1)coutnj.getrg();ycij=nj.getrg();if(flag&ENODEk!=)outfu(11,);coutendl;分析符号串intpipei(string&chuan,string&fenxi,string(*yc)50,int&b)charch,a;intx,i,j,k;b+;coutendl9)outfu(8,);elseoutfu(9,);coutfenxi;outfu(26-chuan.length()-fenxi.length(),);coutchuan;outfu(10,);a=chuan0;ch=fe

10、nxifenxi.length()-1;x=ENODE.find(ch);if(x-1)if(ch=a)fenxi.erase(fenxi.length()-1,1);chuan.erase(0,1);couta匹配;if(pipei(chuan,fenxi,yc,b)return1;elsereturn0;)elsereturn0;)else(if(ch=#)(if(ch=a)(cout分析成功endl;return1;)elsereturn0;)elseif(ch=)(fenxi.erase(fenxi.length()-1,1);if(pipei(chuan,fenxi,yc,b)ret

11、urn1;elsereturn0;)else(i=NODE.find(ch);if(a=#)(x=ENODE.find();if(x-1)j=ENODE.length()-1;elsej=ENODE.length();)elsej=ENODE.find(a);if(ycij.length()(coutNODEi-1;k-)if(yci皿k!=)fenxi+=ycijk;if(pipei(chuan,fenxi,yc,b)return1;elsereturn0;elsereturn0;voidmain()edge*n;stringstr,(*yc)50;inti,j,k;boolflag=0;c

12、out请输入上下文无关文法的总规则数：SUM;cout请输入具体规则(格式：左部右部，为空)：endl;n=newedgeSUM;for(i=0;iSUM;i+)for(j=0;jNODE.length()&ENODE.find(strj)ENODE.length()ENODE+=strj;计算first集合for(i=0;iSUM;i+)first(ni,n,i);outfu(10,*);coutendl;for(i=0;iSUM;i+)if(ni.getfirst().find()ni.getfirst().length()if(NODE.find(ni.getro()NODE.lengt

13、h()for(k=1;kni.getrlen();k+)if(NODE.find(ni.getrg()k)NODE.length()(for(j=0；jnj.getfirst().length()(ni.delfirst();break;计算follow集合for(k=0;kSUM;k+)(for(i=0;iSUM;i+)(if(ni.getlf()=n0.getlf()ni.newfollow(#);follow(ni,n,i);for(i=0;iSUM;i+)(for(j=0;jSUM;j+)if(nj.getrg().find(ni.getlf()=nj.getrlen()-1)ni.n

14、ewfollow(nj.getfollow();计算select集合for(i=0;iSUM;i+)(select(ni,n);for(i=0;iNODE.length();i+)(str.erase();for(j=0;jSUM;j+)if(nj.getlf()0=NODEi)(if(!str.length()str=nj.getselect();else(for(k=0;knj.getselect().length();k+)if(str.find(nj.getselect()k)str.length()(flag=1;break;输出coutendl非终Z符;outfu(SUM,);co

15、utFirst;outfu(SUM,);coutFollowendl;outfu(5+SUM,-*-);coutendl;for(i=0;iNODE.length();i+)(for(j=0;jSUM;j+)if(NODEi=nj.getlf()0)(outfu(3,);coutNODEi;outfu(SUM+4,);out(nj.getfirst();outfu(SUM+4-2*nj.getfirst().length(),);out(nj.getfollow();coutendl;break;outfu(5+SUM,-*-);coutendl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文法!endl;)输出预测分析表coutendl预测分析表如下：endl;yc=newstringNODE.Iength()50;outgraph(n,yc);stringchuan,fenxi,fchuan;coutendle-*fsF-TG-TG-A-(?-FG-F-e-e-i请输入符号串圜分析驾森剩余输入串1#E2itCT3ttGGF4tGSiStGCitG7itGT