Weird counting system

[48T7M4Gy]

PS I think simple arrays are OK because the alternative would be to specify incremented addresses

[lastchance]

No loops, no if statements and looks ... horrible. However.

#include <iostream>
#include <iomanip>
#include <string>
using namespace std;

int Age, Base;

//======================================================================

int result( int a, int b, int &carry )           // Special alien arithmetic: 1 digit
{                                                // Inductively, carry is either -1, 0 or 1
   int sum = a + b + carry;                      // Unbounded sum; lies between -Base and +Base
   carry = ( sum + Age ) / Base + ( sum - Age ) / Base;
   return sum - Base * carry;
}

//======================================================================

int main()
{
   Age = 3;                  
   Base = Age + 1 + Age;
   const int Ndigits = 6;

   string leftover[] = { "-1", "  ",  " 1" };    // Any carry-over left at end; needs possible blank
   int a[Ndigits], b[Ndigits], c[Ndigits];

   cout << "Enter the alien's first 6 digits, separated by spaces: ";
   cin >> a[5] >> a[4] >> a[3] >> a[2] >> a[1] >> a[0];
   cout << "Enter the alien's second 6 digits, separated by spaces: ";
   cin >> b[5] >> b[4] >> b[3] >> b[2] >> b[1] >> b[0];

   int carry = 0;
   c[0] = result( a[0], b[0], carry );           // Looks horrible without loops!
   c[1] = result( a[1], b[1], carry );
   c[2] = result( a[2], b[2], carry );
   c[3] = result( a[3], b[3], carry );
   c[4] = result( a[4], b[4], carry );
   c[5] = result( a[5], b[5], carry );

   #define SP << setw( 3 ) <<
   cout << "  "              SP a[5] SP a[4] SP a[3] SP a[2] SP a[1] SP a[0] << '\n';
   cout << "  "              SP b[5] SP b[4] SP b[3] SP b[2] SP b[1] SP b[0] << '\n';
   cout << string( 21, '-' ) << '\n';
   cout << leftover[carry+1] SP c[5] SP c[4] SP c[3] SP c[2] SP c[1] SP c[0] << '\n';
}

Enter the alien's first 6 digits, separated by spaces:  1 -2 3 1 0 -1
Enter the alien's second 6 digits, separated by spaces: 2 0 3 3 -1 -3
    1 -2  3  1  0 -1
    2  0  3  3 -1 -3
---------------------
    3 -1  0 -3 -2  3

Sadly, the OP gives:

6 variable input 1 -2 3 1 0 -1
6 variable input + 2 0 3 3 -1 -3
-------------
= 3 -1 -3 0 -2 3

so something's awry in the middle two digits.

[Duthomhas]

LOL, Nice!