设计一个给定文法和对应的FIRSTVT和LASTVT集,能依据依据文法和FIRSTVT和LASTVT生成算符优先分析表

1、实验二 算符优先分析器#include "stdio.h"#include "stdlib.h"#include "iostream.h"char data2020; /算符优先关系char s100; /模拟符号栈s char lable20; /文法终极符集char input100; /文法输入符号串char string2010; /用于输入串的分析int k; char a; int j; char q; int r; /文法规则个数int r1; /转化后文法规则个数char st1030; /用来存储文法规则char f

2、irst1010; /文法非终结符FIRSTVT集char last1010; /文法非终结符LASTVT集int fflag10=0; /标志第i个非终结符的FIRSTVT集是否已求出int lflag10=0; /标志第i个非终结符的LASTVT集是否已求出int deal(); /对输入串的分析int zhongjie(char c); /判断字符c是否是终极符int xiabiao(char c); /求字符c在算符优先关系表中的下标void out(int j,int k,char *s); /打印s栈void firstvt(char c); /求非终结符c的FIRSTVT集voi

3、d lastvt(char c); /求非终结符c的LASTVT集void table(); /创建文法优先关系表void main()int i,j,k=0; printf("请输入文法规则数：");scanf("%d",&r);printf("请输入文法规则：n");for(i=0;i<r;i+)scanf("%s",sti); /存储文法规则，初始化FIRSTVT集和LASTVT集*/ firsti0=0; /*firsti0和lasti0分别表示sti0非终极符的FIRSTVT集和LASTVT

4、集中元素的个数*/lasti0=0;for(i=0;i<r;i+) /判断文法是否合法for(j=0;stij!='0'j+)if(sti0<'A'|sti0>'Z')printf("不是算符文法!n"); exit(-1);if(stij>='A'&&stij<='Z') if(stij+1>='A'&&stij+1<='Z')printf("不是算符文法!n"); e

5、xit(-1); for(i=0;i<r;i+)for(j=0;stij!='0'j+)if(stij<'A'|stij>'Z')&&stij!='-'&&stij!='>'&&stij!='|')lablek+=stij;lablek='#'lablek+1='0' table();printf("每个非终结符的FIRSTVT集为：n"); /输出每个非终结符的FIRSTVT

6、集for(i=0;i<r;i+)printf("%c: ",sti0);for(j=0;j<firsti0;j+)printf("%c ",firstij+1);printf("n");printf("每个非终结符的LASTVT集为：n"); /输出每个非终结符的LASTVT集for(i=0;i<r;i+)printf("%c: ",sti0);for(j=0;j<lasti0;j+)printf("%c ",lastij+1);printf(&quo

7、t;n");printf("算符优先分析表如下:n");for(i=0;lablei!='0'i+) printf("t%c",lablei);printf("n"); for(i=0;i<k+1;i+)printf("%ct",lablei);for(j=0;j<k+1;j+)printf("%ct",dataij);printf("n");printf("请输入文法输入符号串以#结束:");scanf("

8、%s",input); deal();void table()char text2010;int i,j,k,t,l,x=0,y=0;int m,n;x=0;for(i=0;i<r;i+)firstvt(sti0);lastvt(sti0);for(i=0;i<r;i+)textxy=sti0;y+;for(j=1;stij!='0'j+)if(stij='|')textxy='0'x+;y=0;textxy=sti0;y+;textxy+='-'textxy+='>'elsetextx

9、y=stij;y+;textxy='0'x+;y=0;r1=x;printf("转化后的文法为:n");for(i=0;i<x;i+) /输出转化后的文法规则串printf("%sn",texti);for(i=0;i<x;i+) /*求每个终结符的推导结果(去掉"->"后的转化文法，用于最后的规约)*/stringi0=texti0;for(j=3,l=1;textij!='0'j+,l+)stringil=textij;stringil='0'for(i=0;i&l

10、t;x;i+)for(j=1;textij+1!='0'j+)if(zhongjie(textij)&&zhongjie(textij+1)m=xiabiao(textij);n=xiabiao(textij+1);datamn='='if(textij+2!='0'&&zhongjie(textij)&&zhongjie(textij+2)&&!zhongjie(textij+1)m=xiabiao(textij);n=xiabiao(textij+2);datamn='=

11、'if(zhongjie(textij)&&!zhongjie(textij+1)for(k=0;k<r;k+)if(stk0=textij+1)break;m=xiabiao(textij);for(t=0;t<firstk0;t+)n=xiabiao(firstkt+1);datamn='<'if(!zhongjie(textij)&&zhongjie(textij+1)for(k=0;k<r;k+)if(stk0=textij)break;n=xiabiao(textij+1);for(t=0;t<la

12、stk0;t+)m=xiabiao(lastkt+1);datamn='>'m=xiabiao('#');for(t=0;t<first00;t+)n=xiabiao(first0t+1);datamn='<'n=xiabiao('#');for(t=0;t<last00;t+)m=xiabiao(last0t+1);datamn='>'datann='='void firstvt(char c) /求FIRSTVT集int i,j,k,m,n;for(i=0;i<

13、;r;i+)if(sti0=c)break;if(fflagi=0)n=firsti0+1;m=0;doif(m=2|stim='|')if(zhongjie(stim+1)firstin=stim+1;n+;elseif(zhongjie(stim+2)firstin=stim+2;n+;if(stim+1!=c)firstvt(stim+1);for(j=0;j<r;j+)if(stj0=stim+1)break;for(k=0;k<firstj0;k+)int t;for(t=0;t<n;t+)if(firstit=firstjk+1)break;if(

14、t=n)firstin=firstjk+1;n+;m+;while(stim!='0');firstin='0'firsti0=-n;fflagi=1;void lastvt(char c) /求LASTVT集int i,j,k,m,n;for(i=0;i<r;i+)if(sti0=c)break;if(lflagi=0)n=lasti0+1;m=0;doif(stim+1='0'|stim+1='|')if(zhongjie(stim)lastin=stim;n+;elseif(zhongjie(stim-1)lastin

15、=stim-1;n+;if(stim!=c)lastvt(stim);for(j=0;j<r;j+)if(stj0=stim)break;for(k=0;k<lastj0;k+)int t;for(t=0;t<n;t+)if(lastit=lastjk+1)break;if(t=n)lastin=lastjk+1;n+;m+;while(stim!='0');lastin='0'lasti0=-n;lflagi=1;int deal()int i,j;int x,y;int z; /输入串的长度k=1;sk='#' /栈置初值f

16、or(i=0;inputi!='0'i+); /计算输入串的长度z=i-;i=0;while(a=inputi)!='0')if(zhongjie(sk)j=k;elsej=k-1;x=xiabiao(sj);y=xiabiao(a);if(dataxy='>')out(1,k,s);printf("%c",a);out(i+1,z,input);printf("规约n");doq=sj;if(zhongjie(sj-1)j=j-1;else j=j-2;x=xiabiao(sj);y=xiabiao

17、(q);while(dataxy!='<');int m,n,N;for(m=j+1;m<=k;m+)for(N=0;N<r1;N+)for(n=1;stringNn!='0'n+)if(!zhongjie(sm)&&!zhongjie(stringNn)if(zhongjie(sm+1)&&zhongjie(stringNn+1)&&sm+1=stringNn+1)sj+1=stringN0; break; elseif(zhongjie(sm)if(sm=stringNn)sj+1=strin

18、gN0; break; k=j+1;if(k=2&&a='#')out(1,k,s);printf("%c",a);out(i+1,z,input);printf("结束n");printf("输入串符合文法的定义！n");return 1; /输入串符合文法的定义elseif(dataxy='<'|dataxy='=') /移进out(1,k,s);printf("%c",a);out(i+1,z,input);printf("移进n");k+;sk=a;i+;elseprintf("nflase");return 0;printf("nflase");return 0;void out(int j,int k,char *s)int n=0;int