编译原理实验word程序

#include "basedata.h" #include "symbol.h" #include <conio.h> #include <string.h> #include <ctype.h> char *WORD[WORDLEN]={"BEGIN","CALL","CONST","DO", "END","IF","ODD","PROCEDURE", "READ","THEN","VAR","WHILE", "WRITE" };//保留字字符串表,用于将保留字种别码转为字符串输出 SYMBOL WSYM[WORDLEN]={BEGINSYM,CALLSYM,CONSTSYM, DOSYM,ENDSYM,IFSYM,ODDSYM, PROCSYM,READSYM,THENSYM, VARSYM,WHILESYM,WRITESYM};//保留字种别码表 char* SNAME[SYMBOLNUM]= {"NOL","IDENT","NUMBER","PLUS","MINUS","TIMES", "SLASH","ODDSYM","EQL","NEQ","LSS","LEQ","GTR", "GEQ","LPAREN","RPAREN","LBRACE","RBRACE","COMMA","SEMICOLON", "PERIOD","BECOMES","BEGINSYM","ENDSYM","IFSYM", "THENSYM","WHILESYM","WRITESYM","READSYM", "DOSYM","CALLSYM","CONSTSYM","VARSYM","PROCSYM"}; //单词字符串表,用于将保留字种别码转为字符串输出 SYMBOL sym;//最近已识的单词种别码 char token[MAXIDLEN+1];//最近已识别的单词 int num;//最近已识别的数字值 char ch;//最近已识别的字符 int col=1,row=1;//当前行和列值 FILE *fd;//指向待编译文件 extern FILE *fout;//指向存放结果文件 void Getchar(void) { ch=fgetc(fd); if(ch!=EOF && ch!='\n') col++; return; } void Getbc(void) { while(ch==SPACE ||ch==TABLE ||ch=='\n') { if(ch=='\n') {row++;col=1;} Getchar(); }//为空字符则一直读至不为空字符 } void Retract(void) { fseek(fd,-1l,SEEK_CUR); col--; } void Concat(void) { char temp[2]; temp[0]=ch;temp[1]='\0'; strcat(token,temp); } int Reserve(void) { int i,j; char temp[60]; j=strlen(token); for(i=0;i<j;i++) { temp[i]=toupper(token[i]);//将当前token字以大写形式存入temp中 } temp[i]='\0'; for(i=0;i<WORDLEN;i++) { if(!strcmp(WORD[i],temp)) break; }//判断当前token是否是保留字 if(i>=WORDLEN) i=-1; return i; } void Errorsym(void) { fprintf(fout, "There is error @row: %5d, @col: %5d", row,col); } int Getsym(void) { int k; int flag=TRUE; Getchar(); Getbc();//滤掉白字符 strcpy(token,""); if(isalpha(ch)) { //以字母开头则是标识符 num=0; Concat(); Getchar(); while(isalnum(ch)) { Concat(); Getchar(); } Retract();//由于超前搜索了，所以回退一个字符 k=Reserve();//判断此标识符是否是保留字 if(k!=-1) { sym=WSYM[k];//将保留字种别码存入sym中 } else { sym=IDENT;//将一般标识符种别码存入sym中 }//end else k!=-1; }//end of if isalpha else if(isdigit(ch)) { //以数字开头则为无符号整数 Concat(); Getchar(); while(isdigit(ch)) { Concat(); Getchar(); } if(isalpha(ch)) { flag=FALSE; while(isalnum(ch)) { Concat(); Getchar(); } }//end of flag=FALSE Retract();//回退 if(flag)//若是无符号整数，则将整数值存于num中 {sym=NUMBER;num=atoi(token);} }//end of if isdigit else { num=0; switch (ch) { case '+':Concat();sym=PLUS;break; case '-':Concat();sym=MINUS;break; case '*':Concat();sym=TIMES;break; case '/':Concat();sym=SLASH;break; case '(':Concat();sym=LPAREN;break; case ')':Concat();sym=RPAREN;break; case '{':Concat();sym=LBRACE;break; case '}':Concat();sym=RBRACE;break; case '=':Concat();sym=EQL;break; case '#':Concat();sym=NEQ;break; /* ODDSYM,EQL,NEQ,LSS,LEQ,GTR,GEQ,LPAREN,LBRACE, RBRACE,RPAREN,COMMA,SEMICOLON,PERIOD,BECOMES, */ case ',':Concat();sym=COMMA;break; case '.':Concat();sym=PERIOD;break; case ';':Concat();sym=SEMICOLON;break; case '>': Concat();Getchar(); if(ch!='=')//若后不跟'=',则回退 {sym=GTR;Retract();} else {Concat();sym=GEQ;} break; case '<':Concat();Getchar(); if(ch!='=') {sym=LSS;Retract();} else {Concat();sym=LEQ;} break; case ':':Concat();Getchar(); if(ch!='=') {flag=FALSE;Retract();} else {Concat();sym=BECOMES;} break; default :Concat();flag=FALSE;break; }//end of switch else char }//end of else char return flag; }