#include#include #include #include char prog[80]={'\0'},token[8]; char ch;int syn,n,sum,m,p; char *rwtab[6]={"begin","if","then","while","do","end"};void scaner(){ m=0; sum=0; for(n=0;n<8;n++) token[n]='\0'; ch=prog[p++]; while(ch==' ') ch=prog[p++]; if(isalpha(ch)) { while(isalpha(ch)||isdigit(ch)) { token[m++]=ch; ch=prog[p++]; } token[m++]='\0'; ch=prog[p--]; syn=10; for(n=0;n<6;n++) if(strcmp(token,rwtab[n])==0) { syn=n+1; break; } } else if(isdigit(ch)) { while(isdigit(ch)) { sum=sum*10+ch-'0'; ch=prog[p++]; } ch=prog[p--]; syn=11; } else switch(ch) { case'<':m=0;token[m++]=ch;ch=prog[p++]; if(ch=='>') { syn=21; token[m++]=ch; } else if(ch=='=') { syn=22; token[m++]=ch; } else { syn=20; ch=prog[p--]; } break; case'>':m=0;token[m++]=ch;ch=prog[p++]; if(ch=='=') { syn=24; token[m++]=ch; } else { syn=23; ch=prog[p--]; } break; case':':m=0;token[m++]=ch;ch=prog[p++]; if(ch=='=') { syn=18; token[m++]=ch; } else { syn=17; ch=prog[p--]; } break; case'+':syn=13;token[0]=ch;break; case'-':syn=14;token[0]=ch;break; case'*':syn=15;token[0]=ch;break; case'/':syn=16;token[0]=ch;break; case'=':syn=25;token[0]=ch;break; case';':syn=26;token[0]=ch;break; case'(':syn=27;token[0]=ch;break; case')':syn=28;token[0]=ch;break; case'#':syn=0;token[0]=ch;break; default:syn=-1;}}main(){ p=0; printf("\n请输入需要分析的字符串,以#表示结束:"); do { ch=getchar(); prog[p++]=ch; }while(ch!='#'); p=0; do { scaner(); switch(syn) { case 11: printf("(%d,%d)\n",syn,sum);break; case -1: printf("\n 出错;\n");break; default: printf("(%d,%s)\n",syn,token); } }while(syn!=0); getch();}