新建一个文本文档在你工程目录下，名字起为"输入.txt",里面的内容可以为
begin a:=1+7*(6+3);b:=1end#
输出是在"输出.txt"中查看，以下为输出情况：
词法分析结果如下:
(1, begin)
(10, a)
(18, :=)
(11, 1)
(13, +)
(11, 7)
(15, *)
(27, ()
(11, 6)
(13, +)
(11, 3)
(28, ))
(26, ;)
(10, b)
(18, :=)
(11, 1)
(6, end)
(0, #)
语法分析结果如下:（以四元式形式输出）
( +, 6, 3, t1)
( *, 7, t1, t2)
( +, 1, t2, t3)
( =, t3, __, a)
( =, 1, __, b)
//提供一个编译原理的语义分析程序 你可以直接复制 用TC进行调试
#include "stdio.h"
#include "string.h"
#include <malloc.h>
#include <conio.h>
#include "stdlib.h"
char prog[100],token[8],ch;
char *rwtab[6]={"begin","if","then","while","do","end"};
int syn,p,m,n,sum,q;
int kk;
//四元式表的结构如下：
struct
{
char result1[8];
char ag11[8];
char op1[8];
char ag21[8];
}quad[20];
char *factor();
char *expression();
int yucu();
char *term();
int statement();
int lrparser();
char *newtemp();
void scaner();
void emit(char *result,char *ag1,char *op,char *ag2);
void main()
{
FILE *fp1,*fp2;
if((fp1=fopen("输入.txt","rt"))==NULL)
{
printf("Cannot open 输入.txt\n");
getch();
exit(1);
}
if((fp2=fopen("输出.txt","wt+"))==NULL)
{
printf("Cannot create 输出.txt FILE.strike any key exit");
getch();
exit(1);
}
int j;
q=p=kk=0;
p=0;
//printf("Please Input a String(end with '#'):\n");
while(ch!='#')
{
ch = fgetc(fp1);
if(ch == EOF)
{
printf("文件为空，请检查后再尝试!");
return ;
}
prog[p++]=ch;
}
if(prog[p]=='#')
{
printf("输入的待分析的串不是以'#'结尾,请修改之后再尝试!\n");
return;
}
p=0;
char buffer1[200] = {0};
sprintf(buffer1,"词法分析结果如下:\n");
fputs(buffer1,fp2);
//printf("词法分析结果如下:\n");
do
{
scaner();
switch(syn)
{
case 11:
//printf("(%d,%d)\n",syn,sum);
sprintf(buffer1,"(%d, %d) \n",syn,sum);
fputs(buffer1,fp2);
break;
default:
//printf("(%d,%s)\n",syn,token);
sprintf(buffer1,"(%d, %s)\n",syn,token);
fputs(buffer1,fp2);
break;
}
}while(syn!=0);
printf("\n");
p=0;
char buffer[200]={0};
sprintf(buffer,"语法分析结果如下:（以四元式形式输出）\n");
fputs(buffer,fp2);
//printf("语法分析结果如下:（以四元式形式输出）\n");
scaner();//扫描函数
lrparser();
if(q>19)
printf(" to long sentense!\n");
else
{
for (j=0;j<q;j++)
{
//printf("( %s, %s, %s, %s) \n\n",quad[j].op1,quad[j].ag11,quad[j].ag21,quad[j].result1);
sprintf(buffer,"( %s, %s, %s, %s) \n\n",quad[j].op1,quad[j].ag11,quad[j].ag21,quad[j].result1);
fputs(buffer,fp2);
}
}
printf("已把相应的词法和语法的结果保存到相应的文件中，请查阅!\n");
fclose(fp1);
fclose(fp2);
}
int lrparser()
{
int schain=0;
kk=0;
if (syn==1) //得到begin
{
scaner();//扫描下个字符
schain=yucu();
if(syn==6)//得到end
{
scaner();//扫描下个字符
if((syn==0)&&(kk==0)) //得到#
printf("Success!\n");
}
else
{
if(kk!=1)
printf("short of 'end' !\n");
kk=1;
getch();
exit(0);
}
}
else
{
printf("short of 'begin' !\n");
kk=1;
getch();
exit(0);
}
return (schain);
}
int yucu()
{
int schain=0;
schain=statement();
while(syn==26)
{
scaner();
schain=statement();
}
return (schain);
}
int statement()
{
char tt[8],eplace[8];
int schain=0;
if (syn==10)
{
strcpy(tt,token); //tt中保存的是第一个字符
scaner();
if(syn==18) //检测到=号
{
scaner();
strcpy(eplace,expression());
emit(tt,eplace,"=","__");
schain=0;
}
else
{
printf("short of sign ':=' !\n");
kk=1;
getch();
exit(0);
}
return (schain);
}
}
char *expression()
{
char *tp,*ep2,*eplace,*tt;
tp=(char *)malloc(12);
ep2=(char *)malloc(12);
eplace=(char *)malloc(12);
tt=(char *)malloc(12);
strcpy(eplace,term());
while((syn==13)||(syn==14))
{
if (syn==13)
strcpy(tt,"+");
else
strcpy(tt,"-");
scaner();
strcpy(ep2,term());
strcpy(tp,newtemp());
emit(tp,eplace,tt,ep2);
strcpy(eplace,tp);
}
return (eplace);
}
char *term()
{
char *tp,*ep2,*eplace,*tt;
tp=(char *)malloc(12);
ep2=(char *)malloc(12);
eplace=(char *)malloc(12);
tt=(char *)malloc(12);
strcpy(eplace,factor());
while((syn==15)||(syn==16))
{
if (syn==15)
strcpy(tt,"*");
else
strcpy(tt,"/");
scaner();
strcpy(ep2,factor());
strcpy(tp,newtemp());
emit(tp,eplace,tt,ep2);
strcpy(eplace,tp);
}
return (eplace);
}
char *factor()
{
char *fplace;
fplace=(char *)malloc(12);
strcpy(fplace,"");
if(syn==10) //得到字符
{
strcpy(fplace,token);
scaner();
}
else if(syn==11) //得到数字
{
itoa(sum,fplace,10);
scaner();
}
else if(syn==27) //得到)
{
scaner();
fplace=expression();
if(syn==28) //得到(
scaner();
else
{
printf("error on ')' !\n");
kk=1;
getch();
exit(0);
}
}
else
{
printf("error on '(' !\n");
kk=1;
getch();
exit(0);
}
return (fplace);
}
//该函数回送一个新的临时变量名，临时变量名产生的顺序为T1,T2...
char *newtemp()
{
char *p;
char m[8];
p=(char *)malloc(8);
kk++;
itoa(kk,m,10);
strcpy(p+1,m);
p[0]='t';
return(p); //设置中间变量名放在一个字符数组中，字符数组的第一个字符为t第二个字符为m表示的数值
}
void scaner()
{
sum=0;
///for(m=0;m<8;m++)
//token[m++]=NULL;
memset(token,0,8);
m=0;
ch=prog[p++];
while(ch==' ')
ch=prog[p++];
if(((ch<='z')&&(ch>='a'))||((ch<='Z')&&(ch>='A')))
{
while(((ch<='z')&&(ch>='a'))||((ch<='Z')&&(ch>='A'))||((ch>='0')&&(ch<='9')))
{
token[m++]=ch;
ch=prog[p++];
}
p--;
syn=10;
token[m++]='\0';
for(n=0;n<6;n++)
if(strcmp(token,rwtab[n])==0)
{
syn=n+1;
break;
}
}
else if((ch>='0')&&(ch<='9'))
{
while((ch>='0')&&(ch<='9'))
{
sum=sum*10+ch-'0';
ch=prog[p++];
}
p--;
syn=11;
}
else switch(ch)
{
case '<':m=0;
ch=prog[p++];
if(ch=='>')
{
syn=21;
}
else if(ch=='=')
{
syn=22;
}
else
{
syn=20;
p--;
}
break;
case '>':m=0;
ch=prog[p++];
if(ch=='=')
{
syn=24;
}
else
{
syn=23;
p--;
}
break;
case ':':m=0;
token[m++] = ch;
ch=prog[p++];
if(ch=='=')
{
syn=18;
token[m++] = ch;
}
else
{
syn=17;
p--;
}
break;
case '+': syn=13;token[0] = ch; break;
case '-': syn=14;token[0] = ch; break;
case '*': syn=15;token[0] = ch;break;
case '/': syn=16;token[0] = ch;break;
case '(': syn=27;token[0] = ch;break;
case ')': syn=28;token[0] = ch;break;
case '=': syn=25;token[0] = ch;break;
case ';': syn=26;token[0] = ch;break;
case '#': syn=0;token[0] = ch;break;
default: syn=-1;break;
}
}
//该函数是生成一个三地址语句送到四元式表中
void emit(char *result,char *ag1,char *op,char *ag2)
{
strcpy(quad[q].result1,result);
strcpy(quad[q].ag11,ag1);
strcpy(quad[q].op1,op);
strcpy(quad[q].ag21,ag2);
q++; //统计有多少个四元式
}
温馨提示：答案为网友推荐，仅供参考