4. Reference Parameter Update

#include <iostream>

// x is passed by reference so changes affect the caller
void update(int& x, int delta) {
    x += delta;
}

int main() {
    int32_t x, delta;
    std::cin >> x >> delta;

    update(x, delta);

    std::cout << x;

    return 0;
}

Explanation & Logic Summary:

• Passing x as a reference (int&) allows the function to modify the original variable.
• delta is passed by value because it is not modified.
• No pointer syntax is required, improving safety and readability.
• The updated value of x persists after the function returns.

Firmware Relevance & Real-World Context:

• Reference parameters are widely used in embedded APIs to update state or configuration values.
• Avoids raw pointer usage while maintaining zero-copy efficiency.
• Common in driver interfaces, HAL layers, and middleware code.
• Reinforces understanding of data ownership and side effects in firmware functions.