最新first集follow集求解算法及构造预测分析表.doc

Four short words sum up what has lifted most successful individuals above the crowd: a little bit more.-author-datefirst集follow集求解算法及构造预测分析表first集follow集求解算法及构造预测分析表构造预测分析表源程序：#include<stdlib.h>#include<stdio.h>#include<string.h>/*/int count=0; /*分解的产生式的个数*/int number; /*所有终结符和非终结符的总数*/char start; /*开始符号*/char termin50; /*终结符号*/char non_ter50; /*非终结符号*/char v50; /*所有符号*/char left50; /*左部*/char right5050; /*右部*/char first5050,follow5050; /*各产生式右部的FIRST和左部的FOLLOW集合*/char first15050; /*所有单个符号的FIRST集合*/char select5050; /*各单个产生式的SELECT集合*/char f50,F50; /*记录各符号的FIRST和FOLLOW是否已求过*/char empty20; /*记录可直接推出的符号*/char TEMP50; /*求FOLLOW时存放某一符号串的FIRST集合*/int validity=1; /*表示输入文法是否有效*/int ll=1; /*表示输入文法是否为LL(1)文法*/int M2020; /*分析表*/char choose; /*用户输入时使用*/char empt20; /*求_emp()时使用*/char fo20; /*求FOLLOW集合时使用*/*判断一个字符是否在指定字符串中*/int in(char c,char *p)int i;if(strlen(p)=0)return(0);for(i=0;i+) if(pi=c) return(1); /*若在，返回1*/if(i=strlen(p) return(0); /*若不在，返回0*/*得到一个不是非终结符的符号*/char c()char c='A' while(in(c,non_ter)=1)c+;return(c);/*分解含有左递归的产生式*/void recur(char *point) /*完整的产生式在point中*/ int j,m=0,n=3,k;char temp20,ch;ch=c(); /*得到一个非终结符*/k=strlen(non_ter);non_terk=ch;non_terk+1='0'for(j=0;j<=strlen(point)-1;j+) if(pointn=point0) /*如果'|'后的首符号和左部相同*/ for(j=n+1;j<=strlen(point)-1;j+) while(pointj!='|'&&pointj!='0') tempm+=pointj+; leftcount=ch; memcpy(rightcount,temp,m); rightcountm=ch; rightcountm+1='0' m=0; count+; if(pointj='|') n=j+1; break; else /*如果'|'后的首符号和左部不同*/ leftcount=ch; rightcount0='' rightcount1='0' count+; for(j=n;j<=strlen(point)-1;j+) if(pointj!='|') tempm+=pointj; else leftcount=point0; memcpy(rightcount,temp,m); rightcountm=ch; rightcountm+1='0' printf(" count=%d ",count); m=0; count+; leftcount=point0; memcpy(rightcount,temp,m); rightcountm=ch; rightcountm+1='0' count+; m=0;void non_re(char *point) int m=0,j;char temp20;for(j=3;j<=strlen(point)-1;j+) if(pointj!='|') tempm+=pointj;else leftcount=point0; memcpy(rightcount,temp,m); rightcountm='0' m=0; count+; leftcount=point0; memcpy(rightcount,temp,m); rightcountm='0' count+;m=0;/*读入一个文法*/char grammer(char *t,char *n,char *left,char right5050)char vn50,vt50;char s;char p5050;int i,j,k;printf("请输入文法的非终结符号串："); scanf("%s",vn);getchar(); i=strlen(vn); memcpy(n,vn,i);ni='0'printf("请输入文法的终结符号串："); scanf("%s",vt);getchar(); i=strlen(vt); memcpy(t,vt,i);ti='0' printf("请输入文法的开始符号：");scanf("%c",&s);getchar();printf("请输入文法产生式的条数："); scanf("%d",&i);getchar(); for(j=1;j<=i;j+)printf("请输入文法的第%d条（共%d条）产生式：",j,i);scanf("%s",pj-1); getchar(); for(j=0;j<=i-1;j+)if(pj1!='-'|pj2!='>') printf("ninput error!"); validity=0; return('0'); /*检测输入错误*/ for(k=0;k<=i-1;k+) /*分解输入的各产生式*/ if(pk3=pk0) recur(pk);else non_re(pk);return(s);/*将单个符号或符号串并入另一符号串*/void merge(char *d,char *s,int type) /*d是目标符号串，s是源串，type1，源串中的' '一并并入目串； type2，源串中的' '不并入目串*/ int i,j;for(i=0;i<=strlen(s)-1;i+) if(type=2&&si='') ;else for(j=0;j+) if(j<strlen(d)&&si=dj) break; if(j=strlen(d) dj=si; dj+1='0' break; /*求所有能直接推出的符号*/void emp(char c) /*即求所有由' '推出的符号*/char temp10;int i;for(i=0;i<=count-1;i+)if(righti0=c&&strlen(righti)=1) temp0=lefti; temp1='0' merge(empty,temp,1); emp(lefti);/*求某一符号能否推出' '*/int _emp(char c) /*若能推出，返回1；否则，返回0*/int i,j,k,result=1,mark=0;char temp20;temp0=c;temp1='0'merge(empt,temp,1);if(in(c,empty)=1)return(1);for(i=0;i+)if(i=count) return(0);if(lefti=c) /*找一个左部为c的产生式*/ j=strlen(righti); /*j为右部的长度*/ if(j=1&&in(righti0,empty)=1) return(1); else if(j=1&&in(righti0,termin)=1) return(0); else for(k=0;k<=j-1;k+) if(in(rightik,empt)=1) mark=1; if(mark=1) continue; else for(k=0;k<=j-1;k+) result*=_emp(rightik); temp0=rightik; temp1='0' merge(empt,temp,1); if(result=0&&i<count) continue; else if(result=1&&i<count) return(1);/*判断读入的文法是否正确*/int judge() int i,j;for(i=0;i<=count-1;i+)if(in(lefti,non_ter)=0) /*若左部不在非终结符中，报错*/ printf("nerror1!"); validity=0; return(0);for(j=0;j<=strlen(righti)-1;j+) if(in(rightij,non_ter)=0&&in(rightij,termin)=0&&rightij!='') /*若右部某一符号不在非终结符、终结符中且不为' '，报错*/ printf("nerror2!"); validity=0; return(0); return(1);/*求单个符号的FIRST*/void first2(int i) /*i为符号在所有输入符号中的序号*/ char c,temp20;int j,k,m;c=vi;char ch=''emp(ch);if(in(c,termin)=1) /*若为终结符*/ first1i0=c; first1i1='0' else if(in(c,non_ter)=1) /*若为非终结符*/for(j=0;j<=count-1;j+) if(leftj=c) if(in(rightj0,termin)=1|rightj0='') temp0=rightj0; temp1='0' merge(first1i,temp,1); else if(in(rightj0,non_ter)=1) if(rightj0=c) continue; for(k=0;k+) if(vk=rightj0) break; if(fk='0') first2(k); fk='1' merge(first1i,first1k,2); for(k=0;k<=strlen(rightj)-1;k+) empt0='0' if(_emp(rightjk)=1&&k<strlen(rightj)-1) for(m=0;m+) if(vm=rightjk+1) break; if(fm='0') first2(m); fm='1' merge(first1i,first1m,2); else if(_emp(rightjk)=1&&k=strlen(rightj)-1) temp0='' temp1='0' merge(first1i,temp,1); else break; fi='1'/*求各产生式右部的FIRST*/void FIRST(int i,char *p)int length;int j,k,m;char temp20;length=strlen(p);if(length=1) /*如果右部为单个符号*/if(p0='') if(i>=0) firsti0='' firsti1='0' else TEMP0='' TEMP1='0' else for(j=0;j+) if(vj=p0) break; if(i>=0) memcpy(firsti,first1j,strlen(first1j); firstistrlen(first1j)='0' else memcpy(TEMP,first1j,strlen(first1j); TEMPstrlen(first1j)='0' else /*如果右部为符号串*/for(j=0;j+) if(vj=p0) break;if(i>=0) merge(firsti,first1j,2);else merge(TEMP,first1j,2);for(k=0;k<=length-1;k+) empt0='0' if(_emp(pk)=1&&k<length-1) for(m=0;m+) if(vm=rightik+1) break; if(i>=0) merge(firsti,first1m,2); else merge(TEMP,first1m,2); else if(_emp(pk)=1&&k=length-1) temp0='' temp1='0' if(i>=0) merge(firsti,temp,1); else merge(TEMP,temp,1); else if(_emp(pk)=0) break;/*求各产生式左部的FOLLOW*/void FOLLOW(int i)int j,k,m,n,result=1;char c,temp20;c=non_teri; /*c为待求的非终结符*/temp0=c;temp1='0'merge(fo,temp,1);if(c=start) /*若为开始符号*/temp0='#'temp1='0'merge(followi,temp,1); for(j=0;j<=count-1;j+)if(in(c,rightj)=1) /*找一个右部含有c的产生式*/ for(k=0;k+) if(rightjk=c) break; /*k为c在该产生式右部的序号*/ for(m=0;m+) if(vm=leftj) break; /*m为产生式左部非终结符在所有符号中的序号*/ if(k=strlen(rightj)-1) /*如果c在产生式右部的最后*/ if(in(vm,fo)=1) merge(followi,followm,1); continue; if(Fm='0') FOLLOW(m); Fm='1' merge(followi,followm,1); else /*如果c不在产生式右部的最后*/ for(n=k+1;n<=strlen(rightj)-1;n+) empt0='0' result*=_emp(rightjn); if(result=1) /*如果右部c后面的符号串能推出*/ if(in(vm,fo)=1) /*避免循环递归*/ merge(followi,followm,1); continue; if(Fm='0') FOLLOW(m); Fm='1' merge(followi,followm,1); for(n=k+1;n<=strlen(rightj)-1;n+) tempn-k-1=rightjn; tempstrlen(rightj)-k-1='0' FIRST(-1,temp); merge(followi,TEMP,2); Fi='1'/*判断读入文法是否为一个LL(1)文法*/int ll1() int i,j,length,result=1;char temp50;for(j=0;j<=49;j+) /*初始化*/firstj0='0' followj0='0'first1j0='0'selectj0='0'TEMPj='0'tempj='0'fj='0'Fj='0'for(j=0;j<=strlen(v)-1;j+) first2(j); /*求单个符号的FIRST集合*/printf("n各非终结符导出的first集:");for(j=0;j<=strlen(v)-1;j+)printf("%c:%s ",vj,first1j); printf("n能导空的非终结符集合:%s",empty);/ printf("n_emp:");/for(j=0;j<=strlen(v)-1;j+) / printf("%d ",_emp(vj);for(i=0;i<=count-1;i+) FIRST(i,righti); /*求FIRST*/for(j=0;j<=strlen(non_ter)-1;j+) /*求FOLLOW*/if(foj=0) fo0='0' FOLLOW(j); /printf("nfirst:");/for(i=0;i<=count-1;i+) / printf("%s ",firsti);printf("nfollow集合:"); for(i=0;i<=strlen(non_ter)-1;i+) printf("%s ",followi);for(i=0;i<=count-1;i+) /*求每一产生式的SELECT集合*/ memcpy(selecti,firsti,strlen(firsti); selectistrlen(firsti)='0'for(j=0;j<=strlen(righti)-1;j+) result*=_emp(rightij);if(strlen(righti)=1&&righti0='') result=1;if(result=1) for(j=0;j+) if(vj=lefti) break; merge(selecti,followj,1);printf("nselect集合顺序是:");for(i=0;i<=count-1;i+) printf("%s ",selecti);memcpy(temp,select0,strlen(select0);tempstrlen(select0)='0'for(i=1;i<=count-1;i+) /*判断输入文法是否为LL(1)文法*/ length=strlen(temp);if(lefti=lefti-1) merge(temp,selecti,1); if(strlen(temp)<length+strlen(selecti) return(0);else temp0='0' memcpy(temp,selecti,strlen(selecti); tempstrlen(selecti)='0'return(1);/*构造分析表M*/void MM() int i,j,k,m;for(i=0;i<=19;i+)for(j=0;j<=19;j+) Mij=-1; i=strlen(termin); termini='#' /*将#加入终结符数组*/ termini+1='0'for(i=0;i<=count-1;i+) for(m=0;m+) if(non_term=lefti) break; /*m为产生式左部非终结符的序号*/for(j=0;j<=strlen(selecti)-1;j+) if(in(selectij,termin)=1) for(k=0;k+) if(termink=selectij) break; /*k为产生式右部终结符的序号*/ Mmk=i;/*判断符号串是否是该文法的句型*/void syntax()int i,j,k,m,n,p,q; char ch;char S50,str50; printf("请输入该文法的句型：");scanf("%s",str);getchar();i=strlen(str);stri='#'stri+1='0'S0='#'S1=start;S2='0'j=0;ch=strj; while(1)if(in(Sstrlen(S)-1,termin)=1) if(Sstrlen(S)-1!=ch) printf("该符号串不是文法的句型！"); return; else if(Sstrlen(S)-1='#') printf("该符号串是文法的句型."); return; else Sstrlen(S)-1='0' j+; ch=strj; else for(i=0;i+) if(non_teri=Sstrlen(S)-1) break; for(k=0;k+) if(termink=ch) break; if(k=strlen(termin) printf("词法错误！"); return; if(Mik=-1) printf("语法错误！"); return; else m=Mik