#include <iostream>
using namespace std;

struct encoder {
    uint32_t val;

    encoder(uint32_t _val = 0) : val(_val) {}

    uint32_t first(uint32_t v = 0) {
        if (!v) return (val << (8*3)) >> (8*3);

        val |= v;
    }

    uint32_t second(uint32_t v = 0) {
        if (!v) return (val << (8*2)) >> (8*3);

        encoder _backupval(val);

        val = (val >> (8*1));
        val |= v;
        val = (val << (8*1));
        val |= _backupval.first();
		return val;
    }

    uint32_t third(uint32_t v = 0) {
        if (!v) return (val << (8*1)) >> (8*3);

        encoder _backupval(val);

        val = (val >> (8*2));
        val |= v;
        //now restore
        val = val << 8;
        val |= _backupval.second();
        val = val << 8;
        val |= _backupval.first();
		return val;
    }

    uint32_t fourth(uint32_t v = 0) {
        if (!v) return (val << (8*0)) >> (8*3);

        encoder _backupval(val);

        val = (val >> (8*3));
        val |= v;
        //now restore
		val = val << 8;
        val |= _backupval.third();
        val = val << 8;
        val |= _backupval.second();
        val = val << 8;
        val |= _backupval.first();        
    }
};

int main() {
    encoder t;
    t.first(6);
    t.second(42);
    t.third(212);
    t.fourth(23);

    cout << "first number: " << t.first()
         << "\nsecond number: " << t.second()
         << "\nthird number: " << t.third()
         << "\nfourth number: " << t.fourth() << endl;

}