编译原理+词法分析器论文

le(IsLetter(ch)||IsDigit(ch)){if((ch<='Z')&&(ch>='A'))ch=ch+32; arr=arr+ch;ch=fgetc(fpin);}fseek(fpin,-1L,SEEK_CUR);  if(Iskey(arr)){cout<<arr<<"\t$属于关键字"<<endl;}  else cout<<arr<<"\t$属于普通标识符"<<endl;     }elseif(IsDigit(ch)){while(IsDigit(ch)||ch=='.'&&IsDigit(fgetc(fpin))){arr=arr+ch;ch=fgetc(fpin);}fseek(fpin,-1L,SEEK_CUR);cout<<arr<<"\t$属于无符号实数"<<endl; }elseswitch(ch){     case'+':case'-':case'*':case'=':case'/':cout<<ch<<"\t$属于运算符"<<endl;break;case'(':case')':case'[':case']':       case';':case'.':case',':case'{':case'}':cout<<ch<<"\t$属于界符"<<endl;break;case':':{ch=fgetc(fpin);if(ch=='=')cout<<":="<<"\t$属于运算符"<<endl;else{cout<<"="<<"\t$属于运算符"<<endl;;fseek(fpin,-1L,SEEK_CUR);}}break;case'>':{ch=fgetc(fpin);if(ch=='=')cout<<">="<<"\t$属于运算符"<<endl;if(ch=='>')cout<<">>"<<"\t$属于输入控制符"<<endl;