#include<stdio.h> #include<string.h> #include <conio.h> #include <ctype.h> char prog[80],token[8],ch; int p,syn,m,n,sum; char *rwtab[6]={"begin","if","then","while","do","end"}; scaner() { sum=0; for(m=0;m<8;m++) token[m]=' '; ch=prog[p++]; m=0; while((ch==' ')||(ch==' ')) ch=prog[p++]; if(((ch<='z')&&(ch>='a'))||((ch<='Z')&&(ch>='A'))) { while(((ch<='z')&&(ch>='a'))||((ch<='Z')&&(ch>='A'))||((ch>='0')&&(ch<='9'))) {token[m++]=ch; ch=prog[p++]; } p--; syn=10; for(n=0;n<6;n++) if(strcmp(token,rwtab[n])==0) { syn=n+1; break; } } else if((ch>='0')&&(ch<='9')) { while((ch>='0')&&(ch<='9')) { sum=sum*10+ch-'0'; ch=prog[p++]; } p--; syn=11; } else switch(ch) { case '<':token[m++]=ch; ch=prog[p++]; if(ch=='=') { syn=21; token[m++]=ch; } else if(ch=='>'){ syn=22; token[m++]=ch; } else { syn=20; p--; } break; case '>':token[m++]=ch; ch=prog[p++]; if(ch=='=') { syn=24; token[m++]=ch; } else { syn=23; p--; } break; case '+':syn=13; token[m++]=ch; break; case '-':syn=14; token[m++]=ch; break; case '*': syn=15; token[m++]=ch; break; case '/': syn=16; token[m++]=ch; break; case ':': token[m++]=ch; ch=prog[p++]; if(ch=='=') { syn=18; token[m++]=ch; } else { syn=17; p--; } break; case '=':syn=25; token[m++]=ch; break; case '(': syn=27; token[m++]=ch; break; case ')': syn=28; token[m++]=ch; break; case ';': syn=26; token[m++]=ch; break; case '#': syn=0; token[m++]=ch; break; default: syn=-1; break; } token[m++]=' '; } main() { p=0; printf(" please input a string(end with #): "); do{ scanf("%c",&ch); prog[p++]=ch; }while(ch!='#'); p=0; do{ scaner(); switch(syn) {case 11:printf("( %-10d%5d ) ",sum,syn); break; case -1:printf("you have input a wrong string "); getch(); break; default: printf("( %-10s%5d ) ",token,syn); break; } }while(syn!=0); getch(); }
