Maqsat Batyrqul

#include <iostream>

using namespace std;

unsigned power10(unsigned y) {
    unsigned result = 1;
    while(y--)
        result = (result << 3) + (result << 1);
    return result;
}

int sign(int a) {
    if(a < 0)
        return -1;
    else
        return 1;
}

void swap(int& a, int& b, unsigned k, unsigned l) {
    const int multiply_a = power10(k);
    const int multiply_b = power10(l);
    const int digit_a    = sign(a) * (a / multiply_a) % 10;
    const int digit_b    = sign(b) * (b / multiply_b) % 10;
    const int add_a = multiply_a * digit_b - multiply_a * digit_a;
    const int add_b = multiply_b * digit_a - multiply_b * digit_b;

    a = a + sign(a)*add_a;
    b = b + sign(b)*add_b;
}

int main() {
    {
        int a = 12345;
        int b = 98765;
        cout << a << ", " << b << " : ";
        swap(a, b, 1, 4);
        cout << a << ", " << b << endl;
    }
    {
        int a = -12345;
        int b = 98765;
        cout << a << ", " << b << " : ";
        swap(a, b, 1, 4);
        cout << a << ", " << b << endl;
    }
    {
        int a = -12345;
        int b = -98765;
        cout << a << ", " << b << " : ";
        swap(a, b, 1, 4);
        cout << a << ", " << b << endl;
    }
    return 0;
}