hdu2024C语言合法标识符

 #include<iostream>
 #include<stdio.h>
 #include<math.h>
 #include<stdlib.h>
 #include<string.h>
 #include<limits>
 using namespace std;

 int main()
 {
     //freopen("in.txt","r",stdin);
     int n;
     char a[];
     cin>>n;
     getchar();
     while(n--)
     {
         gets(a);
         int flag=;
         for(int i=;i<strlen(a);i++)
         {
             if(a[i]=='_' || (a[i]>='' && a[i]<='') || (a[i]>='A' && a[i]<='Z') || (a[i]>='a' && a[i]<='z') )
             {
                 if(i== && (a[i]>='' && a[i]<=''))
                 {
                     flag=;
                     break;
                 }
                 continue;
             }
             else
             {
                 flag=;
                 break;
             }
         }
         if(flag)
         cout<<"no"<<endl;
         else
         cout<<"yes"<<endl;
     }
     return ;
 }