編譯原理實驗詞法分析器

1、#include "stdio.h"#include "string.h"#include "stdlib.h"char key89="if","int","for","while","do","return","break","continue" /保留字char operater103="+","-","*",&q

2、uot;/","=",">","<",">+","<+","!=" /運算符char delimiter62=",","","","","(",")" /分隔符char real102="1","2","3","4","5",

3、"6","7","8","9","."int main()int i=0;void part();char name10,source100;printf("請輸入文件名:n");scanf("%s",&name);FILE *fp; /文件操作if(fp=fopen(name,"r")=NULL) /打開文件printf("File open error!n");exit(0);while(!feof(fp

4、)sourcei=fgetc(fp);i+;sourcei-1='0'printf("分離結果為:n");part();return 0;void part()int i=0;int j,k,flag,flag1; /flag為是否已判斷的標志 flag1為常量的標志char source100;char midest50; /中間數(shù)組，臨時存放分離的單詞while(sourcei!='0') /逐個讀入字符組成單獨的單詞j=0;flag=0;flag1=0;domidestj=sourcei;i+;j+; /當不是分隔符和運算符和其他定義的

5、符號時 繼續(xù)循環(huán)while(sourcei!=' '&&sourcei!='+'&&sourcei!='-'&&sourcei!='*'&&sourcei!='/'&&sourcei!='='&&sourcei!='>'&&sourcei!='<'&&sourcei!='>+'&&source

6、i!='<+'&&sourcei!='!='&&sourcei!=','&&sourcei!=''&&sourcei!=''&&sourcei!=''&&sourcei!='('&&sourcei!=')');midestj='0' /退出循環(huán)時把最后一個存儲單元定義為0作為字符串的結束符 /判斷midest數(shù)組中的內容 /判斷是否為保

7、留字for(k=0;k<8;k+)if(strcmp(midest,keyk)=0)printf("(%s,1)n",midest); /輸出保留字flag=1;break; if(flag=0) /判斷是否為常量for(k=0;midestk!='0'k+)if(midestk<48 | midestk>57 )flag1=1;break;if(flag1=0)printf("(%s,3)n",midest);/輸出常量flag=1;if(flag=0) /判斷是否輸入錯誤，如果無錯誤，則是標識符if(midest0&

8、gt;=48 && midest0<=57)printf("%s輸入錯誤!n",midest);elsefor(k=1;midestk!='0'k+)if(midestk>='a' && midestk<='z')|(midestk>='A' && midestk<='Z')|(midestk>='1' && midestk<='9')|(midestk=&#

9、39;_')|(midestk='#')|(midestk='.')flag=0;elseflag=1;break;if(flag=0)printf("(%s,2)n",midest);elseprintf("%s輸入錯誤!n",midest);if(sourcei=' ')i+;if(sourcei='+'|sourcei='-'|sourcei='*'|sourcei!='/'|sourcei='='|sourcei

10、='>'|sourcei='<'|sourcei='>+'|sourcei='<+'&&sourcei='!='|sourcei=','|sourcei=''|sourcei=''|sourcei=''|sourcei='('|sourcei=')')j=0;flag=0;midestj=sourcei;midestj+1='0'if(flag=0)for(k=0;k<10;k+)if(strcmp(midest,operaterk)=0) /看是不是運算符if(midestj='>'|midestj='<') /如果是運算符 再判斷是不是<號或>號 如果是 再查看后面有沒有=號 if(sourcei+1='=')midestj+1=sourcei+1; /如果有=號 就讓=跟在>或<號后面輸出midestj+2='0'i+;printf("(