pl0词法分析器

1、#include #include #include char ch;FILE *fp;char Getchar2()ch=fgetc(fp);if(ch= |ch=10|ch=9)ch=fgetc(fp);return ch;char Getchar()ch=fgetc(fp);return ch;bool IsLetter()/判断ch是否为字母if(ch=a | ch=A)return true;elsereturn false;bool IsDigit()/判断ch是否为数字if(ch=0)return true;else return false;void Concat(char s

2、trToken30)/将ch中的字符加入strToken中int i=0;while(strTokeni!=0)i+;strTokeni=ch;strTokeni+1=0;int Reserve(char str)if(strcmp(str,begin)=0)return 1;else if(strcmp(str,call)=0)return 2;else if(strcmp(str,const)=0)return 3;else if(strcmp(str,do)=0)return 4;else if(strcmp(str,end)=0)return 5;else if(strcmp(str,

3、if)=0)return 6;else if(strcmp(str,odd)=0)return 7;else if(strcmp(str,procedure)=0)return 8;else if(strcmp(str,read)=0)return 9;else if(strcmp(str,program)=0)return 10;else if(strcmp(str,var)=0)return 11;else if(strcmp(str,while)=0)return 12;else if(strcmp(str,write)=0)return 13;else if(strcmp(str,th

4、an)=0)return 14;else return 0;int InsertConst(char str)int i,value=0;for(i=0;stri!=0;i+)value=10*value+stri-0;return value;void main()int code , value;char id30=;char strToken30;if(fp=fopen(1.txt,r)=NULL)printf(文件打开失败!n);exit(0);ch=Getchar2();/读取一个非空字符while(ch!=EOF)strcpy(strToken,id);if(IsLetter()w

5、hile( IsLetter() | IsDigit() )Concat(strToken);ch=Getchar();code=Reserve(strToken);/保留字返回它代码，否则返回0值if(code=0)printf(n,strToken);elseswitch(code)case 1:printf(n);break;case 2:printf(n);break;case 3:printf(n);break;case 4:printf(n);break;case 5:printf(n);break;case 6:printf(n);break;case 7:printf(n);b

6、reak;case 8:printf(n);break;case 9:printf(n);break;case 10:printf(n);break;case 11:printf(n);break;case 12:printf(n);break;case 13:printf(n);break;case 14:printf(n);break;else if(IsDigit()while(IsDigit()Concat(strToken);ch=Getchar();value=InsertConst(strToken);printf(n,value);elseif(ch=*)ch=Getchar(

7、);if(ch=*)printf(n);else printf(n);else if(ch=)printf(-n);/ ch=Getchar();else if(ch=)printf(n);/ =ch=Getchar();elseprintf(n);/ )ch=Getchar();if(ch=)printf(=-n);/=ch=Getchar();elseprintf(-n);/else if(ch=:)ch=Getchar();if(ch=)printf(n);/=ch=Getchar();elseprintf(n);/else if(ch=+)printf(n); else if(ch=)printf(n);else if(ch=-)printf(n);else if(ch=/)printf(n);else if(ch=;)printf(n);else if(ch=,)printf(n);else if(ch=.)printf(n);else if(ch=()printf(n);else if(ch=)prin