bool, not working

[Nipa]

Hi, I get this error and warning

error: no match for 'operator!' in '!vast'
note: candidate is: operator!(bool) <built-in>

In my bool function which is.

bool tyhjarivi(string vast)
{
   string::size_type i=0;
   while(vast.size()!=0)
     {
        if( !isspace(vast.at(i)) && !vast=="")
          {
             return false;
          }
        vast.erase(i);
     }
   return true;
}

Anyone?

[Disch]

The compiler thinks you're doing (!vast)==""

What you want to do is this: vast!=""