Thread: isdigit function help!!

I read that isdigit() fn returns a non-zero number, if its argument is a digit(0 to 9) and it returns zero otherwise.....

but consider the program.....

Code:

#include<iostream>
#include<ctype>
int main()
{

         int c=3;
         if(isdigit(c))
         {
                cout<<"good";
         }
         else
         {
                cout<<"bad";
         }
}

The output comes as bad
why? please help.......