小C语言--词法分析程序

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#include <iostream>#include <cstdio>#include <cstring>#include <string>#include <cctype>using namespace std;int iskey(char tmp[]){    if(!strcmp(tmp,"main")||!strcmp(tmp,"else")||!strcmp(tmp,"if")||!strcmp(tmp,"int")||!strcmp(tmp,"for")||!strcmp(tmp,"while"))        return 1;    else return 0;}bool isword(char ch){    if(isalpha(ch)) return true;    else if(isdigit(ch)) return true;    else if(ch=='_') return true;    else return false;}int main(){    char ch,tmp[100];    int i=0;    while(~scanf("%c",&ch)){        if(ch==' '||ch=='\n'||ch=='\t') continue;        else if(ch=='('||ch==')'||ch==','||ch=='{'||ch=='}'||ch==';'){            printf("(boundary,%c)\n",ch);        }        else if(isdigit(ch)){            while(isdigit(ch)){                tmp[i++]=ch;                scanf("%c",&ch);            }            tmp[i]='\0';            printf("(integer,%s)\n",tmp);            i=0;ungetc(ch,stdin);        }        else if(isalpha(ch)||ch=='_'){            while(isword(ch)){                tmp[i++]=ch;                scanf("%c",&ch);            }            tmp[i++]='\0';            i=0;            if(iskey(tmp))                printf("(keyword,%s)\n",tmp);            else                printf("(identifier,%s)\n",tmp);            ungetc(ch,stdin);        }        else if(ch=='+'||ch=='='||ch=='-'||ch=='*'||ch=='/'||ch=='<'||ch=='>'||ch=='!') {            char c=ch;            scanf("%c",&ch);            if(ch=='=')                printf("(operator,%c%c)\n",c,ch);            else{                printf("(operator,%c)\n",c);                ungetc(ch,stdin);            }        }    }    return 0;}