Question

I am trying to write a method in C++ which determines if an integer has letters in its hex representation using stream manipulators without using any for loop.
One way could be to use getline and do some math. Can someone provide hints on the kind of computation required?

I appreciate your helps or using the Circular Arithmetic , But I am looking for something which does not iterate over the string

Answer 1

You can do someting like (only logic operation and one substraction)

 bool has_letters(int num)
 {   
      if(num < 0) num = 0- num; //abs value
      unsigned char * c;
      c = (unsigned char * )(& num)
      for(int i=0;i<sizeof(int),i++)
      {
           if(((c[i] & 0xf) > 0x9) || ((((c[i]>>4) & 0xf) > 0x9) )
               return true;
           //or you can use precomputed table
           //if(table[c[i]])
           //     return true;
      }
      return false;
 }

Trick is that binary representaion of string is allready hex (almost) you just need to chek each nibble