燕大编译原理实验词法分析.doc

#include#include#includeusing namespace std;#define keyword_num 13 #define delimiter_num 5 #define words_num 200 #define str_num 10 /变量定义charstrstr_num; /str用于存放接收的单词charwordswords_numstr_num;inti = 0 , n = -1 ,j=1, k; /i作str的下标，n作数组words行的下标intline_num=1; charc; char*keywordkeyword_num = begin,call,const,do,end,if,odd,procedure,read,then,var,while,write; /关键字13个按照顺序排列便于折半查找chardelimiterdelimiter_num = ( , ) , ; , . , ,; /分界符5个FILE *fout; /存放分词结果的文件ifstream fin; string s; int main() printf(输入文件名:); cins; fin.open(s.c_str(); while(!fin.is_open() printf(文件不存在,请重新输入:); fin.clear(); cins; fin.open(s.c_str(); printf(行 (类别 单词 )n);/打开文件“分析结果.txt”，将分词结果写到该文件中 fout = fopen(分析结果.txt,w); fprintf(fout,行 (类别 单词 )n); if(!fin.eof() c = fin.get(); while(1)/忽略回车、tab键和空格，且当是回车时，行号加1while(c = 10 | c =9 | c = )if(c = 10)+ line_num;if(!fin.eof()c = fin.get(); j=1;if(fin.eof()break;/关键字或标识符的接收，以字母或下划线开头 if(c = a & c = A & c =a&c=A&c=0&c=9|c=_) str+i=c;elsebreak; strcpy(words+n,str);/将分离的词放入word中/折半查找关键字int a=0;int b=keyword_num-1;dok=(a+b)/2;if(strcmp(str,keywordk)=0)a=k+1;while(ab)/输出关键字，以行号，二元组(类型，单词)格式printf(%-5d(关键字 , %-10s)n,line_num, str);fprintf(fout, %-5d(关键字 , %-10s)n,line_num, str);else/输出标识符printf(%-5d(标识符 , %-10s)n,line_num, str);fprintf(fout, %-5d(标识符 , %-10s)n,line_num, str); for(;i=0;i-) stri=0; i=0; /常数接收,以数字或负号开头else if(0 = c & c = 9| c =-|c =.) int flag=0;str0=c;while(1)if(!fin.eof()c = fin.get(); /接收数字或小数点if(0 = c & c = a & c = A & c = a & c = A & c = c | c = 9)j=0;flag=2;break;else j=0;break;/如果该单词含有两个小数点,报错for(k=0;kstr_num-1;k+)for(int q=k+1;q=0;i-)stri=0; i=0; else / 接收运算符或分界符/判断是否为分界符for(k=0;kdelimiter_num;k+)if(c=delimiterk)str0=c;words+n0=c;printf(%-5d(分界符 , %-10c)n, line_num,c);fprintf(fout, %-5d(分界符 , %-10c)n, line_num,c);break;if(k=delimiter_num)/k=delimiter_num时，则它是运算符switch(c) case+:printf(%-5d(运算符 , %-10c)n, line_num,c);fprintf(fout, %-5d(运算符 , %-10c)n, line_num,c);words+n0=c;break;case-:printf(%-5d(运算符 , %-10c)n, line_num,c);fprintf(fout, %-5d(运算符 , %-10c)n, line_num,c);words+n0=c;break;case*:printf(%-5d(运算符 , %-10c)n, line_num,c);fprintf(fout, %-5d(运算符 , %-10c)n, line_num,c);words+n0=c;break;case/:printf( %-5d(运算符 , %-10c)n, line_num,c);fprintf(fout, %-5d(运算符 , %-10c)n, line_num,c);words+n0=c;break;case#:printf( %-5d(运算符 , %-10c)n, line_num,c);fprintf(fout, %-5d(运算符 , %-10c)n, line_num,c);words+n0=c;break;case=:printf( %-5d(运算符 , %-10c)n, line_num,c);fprintf(fout, %-5d(运算符 , %-10c)n, line_num,c);words+n0=c;break;/双字符运算符的接收/双字符可以有!=,:=单字符没有!,:case!:case:str0=c;if(!fin.eof()c = fin.get(); if(c=)str1=c;strcpy(words+n,str);printf(%-5d(运算符 , %-10s)n, line_num,str);fprintf(fout, %-5d(运算符 , %-10s)n, line_num,str);str0=0;str1=0;break;elsej=0;strcpy(words+n,str);printf(%-5d(出错 , %-10s)n, line_num,str);fprintf(fout, %-5d(出错 , %-10s)n, line_num,str);str0=0; break;/双字符有=,单字符有case: str0=c;if(!fin.eof() c = fin.get(); if(c=)str1=c;strcpy(words+n,str);printf(%-5d(运算符 , %-10s)n, line_num,str);fprintf(fout, %-5d(运算符 , %-10s)n, line_num,str);str0=0;str1=0;break;elsej=0;strcpy(words+n,str);printf(%-5d(运算符 , %-10s)n, line_num,str