HDU-ACM-2024

# include <stdio.h># include <string.h>int main (){    int n=0;    scanf ("%d",&n);    getchar ();    while (n--)    {            bool p=true;        int i=1;        char a [52]={0};        gets(a);        if (a[0]=='_'||(a[0]>='A'&&a[0]<='Z')||(a[0]>='a'&&a[0]<='z'))        ;        else            p=false;        for (i=1;i<=strlen(a)-1&&p;i++)        {            if (a[i]=='_'||(a[i]>='A'&&a[i]<='Z')||(a[i]>='a'&&a[i]<='z')||(a[i]>='0'&&a[i]<='9'))                continue;            else            {                p=false;                break;            }        }        printf (p?"yes\n":"no\n");        }    return 0;}