lab4.cpp

#include <ctype.h>
#include <iostream>
#include <string>

using namespace std;

class Alpha {

private:
    unsigned bin;

public:
    Alpha() { bin = 0; };
    Alpha(Alpha& y) { bin = y.bin; };

    Alpha(const char*);

    Alpha operator*(Alpha &);

    friend ostream& operator << (ostream&, Alpha&);
};

Alpha::Alpha(const char* s) {
    bin = 0;

    while (*s) {
        bin |= (1 << (tolower(*s) - 'a')); s++;
    }
}

Alpha Alpha::operator*(Alpha &a)
{
    Alpha z;
    z.bin = this->bin & a.bin;
    return z;
}

ostream& operator << (ostream& out, Alpha& z) {
    unsigned bit = 1;
    int i;
    string str;

    for (int i = 0, k = 0; i<26; i++) {
        if ((z.bin & bit) > 0)
            str += (char)('a' + i);

        bit = bit << 1;
    }
    std::reverse(str.begin(), str.end());
    out << str.c_str();

    return out;
}

int main(int argc, char* argv[]) {
    if (argc < 3)
        return 1;

    Alpha x(argv[1]);
    Alpha y(argv[2]);
    Alpha z;

    z = x * y;

    cout << z;

    return (0);

}