#include #include #include using namespace std; class BalancedTernary {   protected:     // Store the value as a reversed string of +, 0 and - characters     string value;   // Helper function to change a balanced ternary character to an integer   int charToInt(char c) const {     if (c == '0')       return 0;     return 44 - c;   }   // Helper function to negate a string of ternary characters   string negate(string s) const {     for (int i = 0; i < s.length(); ++i) {       if (s[i] == '+')         s[i] = '-';       else if (s[i] == '-')         s[i] = '+';     }     return s;   }   public:     // Default constructor     BalancedTernary() {       value = "0";     }   // Construct from a string   BalancedTernary(string s) {     value = string(s.rbegin(), s.rend());   }   // Construct from an integer   BalancedTernary(long long n) {     if (n == 0) {       value = "0";       return;     }     bool neg = n < 0;     if (neg)       n = -n;     value = "";     while (n != 0) {       int r = n % 3;       if (r == 0)         value += "0";       else if (r == 1)         value += "+";       else {         value += "-";         ++n;       }       n /= 3;     }     if (neg)       value = negate(value);   }   // Copy constructor   BalancedTernary(const BalancedTernary & n) {     value = n.value;   }   // Addition operators   BalancedTernary operator + (BalancedTernary n) const {     n += * this;     return n;   }   BalancedTernary & operator += (const BalancedTernary & n) {     static char * add = "0+-0+-0";     static char * carry = "--000++";     int lastNonZero = 0;     char c = '0';     for (int i = 0; i < value.length() || i < n.value.length(); ++i) {       char a = i < value.length() ? value[i] : '0';       char b = i < n.value.length() ? n.value[i] : '0';       int sum = charToInt(a) + charToInt(b) + charToInt(c) + 3;       c = carry[sum];       if (i < value.length())         value[i] = add[sum];       else         value += add[sum];       if (add[sum] != '0')         lastNonZero = i;     }     if (c != '0')       value += c;     else       value = value.substr(0, lastNonZero + 1); // Chop off leading zeroes     return *this;   }   // Negation operator   BalancedTernary operator - () const {     BalancedTernary result;     result.value = negate(value);     return result;   }   // Subtraction operators   BalancedTernary operator - (const BalancedTernary & n) const {     return operator + (-n);   }   BalancedTernary & operator -= (const BalancedTernary & n) {     return operator += (-n);   }   // Multiplication operators   BalancedTernary operator * (BalancedTernary n) const {     n *= * this;     return n;   }   BalancedTernary & operator *= (const BalancedTernary & n) {     BalancedTernary pos = * this;     BalancedTernary neg = -pos; // Storing an extra copy to avoid negating repeatedly     value = "0";     for (int i = 0; i < n.value.length(); ++i) {       if (n.value[i] == '+')         operator += (pos);       else if (n.value[i] == '-')         operator += (neg);       pos.value = '0' + pos.value;       neg.value = '0' + neg.value;     }     return *this;   }   // Stream output operator   friend ostream & operator << (ostream & out,     const BalancedTernary & n) {     out << n.toString();     return out;   }   // Convert to string   string toString() const {     return string(value.rbegin(), value.rend());   }   // Convert to integer   long long toInt() const {     long long result = 0;     for (long long i = 0, pow = 1; i < value.length(); ++i, pow *= 3)       result += pow * charToInt(value[i]);     return result;   }   // Convert to integer if possible   bool tryInt(long long & out) const {     long long result = 0;     bool ok = true;     for (long long i = 0, pow = 1; i < value.length() && ok; ++i, pow *= 3) {       if (value[i] == '+') {         ok &= LLONG_MAX - pow >= result; // Clear ok if the result overflows         result += pow;       } else if (value[i] == '-') {         ok &= LLONG_MIN + pow <= result; // Clear ok if the result overflows         result -= pow;       }     }     if (ok)       out = result;     return ok;   } }; int main() {   int num, num1, num2, num3;   cout << "enter a: ";   cin >> num;   cout << "enter b: ";   cin >> num1;   cout << "enter c: ";   cin >> num2;   BalancedTernary a(num);   BalancedTernary b(num1);   BalancedTernary c(num2);   cout << "a = " << a.toInt() << " = " << a.toInt() << endl;   cout << "b = " << b.toInt() << " = " << b.toInt() << endl;   cout << "c = " << c.toInt() << " = " << c.toInt() << endl;   cout << "\n";   cout << a.toInt() << " = " << a.toInt() << endl;   BalancedTernary z = c - a;   cout << z.toInt() << " = " << c.toInt() << " - " << a.toInt() << endl;   cout << c.toInt() << " = " << c.toInt() << endl;   BalancedTernary y = c + a;   cout << y.toInt() << " = " << c.toInt() << " + " << a.toInt() << endl;   cout << "\n";   BalancedTernary d = a + b * c;   cout << "a + b * c = " << d.toInt() << "=" << d.toInt() << endl;   return 0; }