hdu 2024 C语言合法标识符

#include<iostream>
#include<string>
using namespace std;
char a[55];

int main()
{
int n;
scanf("%d", &n);
getchar();
while(n--)
{
gets(a);
bool p = true;
if(!(a[0] >= 'a' && a[0] <= 'z') && !(a[0] >= 'A' && a[0] <= 'Z') && a[0] != '_')
p = false;
for(int i = 0; a[i] != '\0'; i++)
{
if(!(a[i] >= 'a' && a[i] <= 'z') && !(a[i] >= 'A' && a[i] <= 'Z') && a[i] != '_' && !(a[i] >= '0' && a[i] <= '9') )
{
p = false; break;
}
}
if(p)
puts("yes");
else
puts("no");
}
return 0;
}