#编译原理实验

1、实验一词法分析器设计【实验目的】1熟悉词法分析的基本原理，词法分析的过程以及词法分析中要注意的问题。2. 复习高级语言，进一步加强用高级语言来解决实际问题的能力。3通过完成词法分析程序，了解词法分析的过程。【实验内容】用C语言编写一个PL/O词法分析器，为语法语义分析提供单词，使之能把输入的字符串形 式的源程序分割成一个个单词符号传递给语法语义分析，并把分析结果（基本字，运算符， 标识符，常数以及界符）输出。【实验步骤和要求】1. 要求绘出词法分析过程的流程图。2. 根据词法分析的目的以及内容，确定完成分析过程所需模块。3. 写出每个模块的源代码。4. 整理程序清单及所得结果。/源程序如下：#

2、in elude <iostream>#include <ctype.h>#include <fstream>#include <string.h>#include <malloc.h>#define NULL "abc"using namespace std;ifstream fp("d:cifa.cpp",ios:in);char cch;char *key12="if","else","for","while"

3、,"do","return","break","continue","int","void" ,"main","const"/ 基本字char *border10= "," , "" , "" , "" , "(" , ")" , "" , "",""&quo

4、t;,""" ;/界符char *arithmetic6="+" , "-" , "*" , "/" , "+" , "-"/ 算术运算符char *relation7="<" , "<=" , "=" , ">" , ">=" , "=" ,"!="/关系运算符char *lable

5、const80;/标识符int constnum=40;int lableconstnum=0;int search(char searchchar,int wordtype)int i=0,t=0;switch (wordtype)case 1:for (i=0;i<=11;i+)if (strcmp(keyi,searchchar)=0)return(i+1);return(0);case 2:for (i=0;i<=9;i+)if (strcmp(borderi,searchchar)=0)return(i+1);return(0);case 3:for (i=0;i<

6、=5;i+)if (strcmp(arithmetici,searchchar)=0)return(i+1);return(0);case 4:for (i=0;i<=6;i+)if (strcmp(relationi,searchchar)=0)return(i+1);return(0);case 5:for (t=40;t<=constnum;t+)if (strcmp(searchchar,lableconstt)=0)return(t+1);lableconstt-1=(char *)malloc(sizeof(searchchar);strcpy(lableconstt-

7、1,searchchar);constnum+;return(t);case 6:for (i=0;i<=lableconstnum;i+)if (strcmp(searchchar,lableconsti)=0)return(i+1);lableconsti-1=(char *)malloc(sizeof(searchchar);strcpy(lableconsti-1,searchchar);lableconstnum+;return(i);default:cout<<" 错误！ "char alphaprocess(char ch)int atype

8、;int i=-1;char alphatp20;while ( (isalpha(ch) | (isdigit(ch) ) alphatp+i=ch; fp.get(ch); alphatpi+1='0'if (atype=search(alphatp,1)cout<<alphatp<<"ttt"<<(atype-1)<<endl; else atype=search(alphatp,6); cout<<alphatp<<"ttt"<<(atype-1)

9、<<endl; return(ch);char digitprocess(char ch)int I = -1;char digittp20;int dtype;while (isdigit(ch) digittp+i=ch; fp.get(ch); digittpi+1='0' dtype=search(digittp,5); cout<<digittp<<"ttt"<<(dtype-40)<<endl; return(ch);char otherprocess(char ch)int i= -1

10、;char othertp20; int otype,otypetp; othertp0=ch; othertp1='0'if (otype=search(othertp,3) fp.get(ch); othertp1=ch; othertp2='0'if (otypetp=search(othertp,3) cout<<othertp<<"ttt"<<(otypetp-1)<<endl; fp.get(ch); goto out;else othertp1='0' cout&l

11、t;<othertp<<"ttt"<<(otype-1)<<endl; goto out;if (otype=search(othertp,4)fp.get(ch); othertp1=ch; othertp2='0'if (otypetp=search(othertp,4) cout<<othertp<<"ttt"<<(otypetp-1)<<endl; fp.get(ch);goto out;else othertp1='0' c

12、out<<othertp<<"ttt"<<(otype-1)<<endl; goto out;if (ch='!') fp.get(ch);if (ch='=')cout<<"!= (2,2)n"fp.get(ch);goto out;elseif (otype=search(othertp,2) cout<<othertp<<"ttt"<<(otype-1)<<endl; fp.get(ch);

13、goto out;if (ch!='n')&&(ch!=' ')cout<<" 错误！ ,字符非法 "<<"ttt"<<ch<<endl; fp.get(ch);out: return(ch);void main()int i;for (i=0;i<=50;i+) lableconsti=NULL; if (!fp) cout<<" 文件打开错误！ ！ "<<endl;elsefp.get (cch);whil

14、e (!fp.eof()if (isalpha(cch) cch=alphaprocess(cch);else if (isdigit(cch) cch=digitprocess(cch);else cch=otherprocess(cch);cout<<" 成功 n" getchar();cifa.cpp#include<stdio.h> void main()cout<< ”Hello World ”;【实验小结】通过这次实验，我对编译原理这门专业必修课有了进一步的深层次了解，把理论知识使用于实验中，也让我重新熟悉 C语言的相关内容，加深了对C语言知识的深化和用途的理解。实验二LL( 1)语法分析程序设计【实验目的】1. 熟