Algorithms

static int tarrifAmounts[] = {0, 10, 20, 40, 100, INT_MAX};
static int tarrifRates[] =   {0, 12, 33, 44, 56,  64};

int bill( int amount )
{
   int ret = 0;
   int tindx = 1;
   while( amount > tarrifAmounts[tindx] )
   {
      ret += tarrifRates[tindx] * (tarrifAmounts[tindx]-tarrifAmounts[tindx-1]);
      tindx++ ;
   }
   ret += tarrifRates[tindx] * (amount - tarrifAmounts[tindx-1]);
   return ret;
}

void memoryFill( void* target, char* pattern, size_t ptrnlen, size_t numRepeats )
{  
   char* trgt = (char*)target;  //for ease in pointer manipulation.   
   ...
   //
   // If we KNEW that memcpy copied from the base of the src array to the base
   // of the target array, we could write an EXTREMELY fast algorithm:
   //    memcpy( trgt, pattern, ptrnlen );                     //put one copy at the base.
   //    memcpy( trgt+ptrnlen, trgt, ptrnlen*(numRepeats-1) ); //destructive copy the rest
   // Conversely, if we KNEW that memcpy copied from the end of the src array 
   // to the end of the target array, we could write:
   //    memcpy( trgt+ptrnlen*(numRepeats-1) , pattern, ptrnlen ); //put one copy at the end.
   //    memcpy( trgt, trgt+ptrnlen, ptrnlen*(numRepeats-1) );     //destructive copy the rest
   // However, the C standard distinctly says that memcpy can do it's copying
   // in whatever order it wants.  We CANNOT rely on any specific order.
   //
   ...
}