Register Overlay byte and bitfield

#include <iostream>
#include <cstdint>
using namespace std;

// Define union Reg with:
// - uint8_t raw
// - struct bits { en:1, mode:3, reserved:4 }
union Reg{
    uint8_t raw;
    struct{
        uint8_t en: 1;
        uint8_t mode: 3;
        uint8_t reserved: 4;
    }bits;
};

int main() {
    unsigned int input;
    cin >> input;

    uint8_t val = static_cast<uint8_t>(input);

    Reg r;
    r.raw = val;

    // Print numeric values (NOT characters)
    cout << "en=" << static_cast<int>(r.bits.en)
         << " mode=" << static_cast<int>(r.bits.mode);

    return 0;
}

Solving Approach