debbynirwan

constexpr int Sum(const int a, const int b) {
    return a + b;
}

constexpr int main(int argc, char **argv) {
    const int val = Sum(1, 2);
    return 0;
}

debbynirwan

int main() {
    constexpr int val = 1 + 2;
    return 0;
}

debbynirwan

int Sum(const int a, const int b) {
    return a + b;
}

int main(int argc, char **argv) {
    const int val = Sum(1, 2);
    return 0;
}

debbynirwan

int main() {
    const int val = 1 + 2;
    return 0;
}

debbynirwan

void callback(const int *value) {
    int *mutableValue = const_cast<int*>(value);
    // we can now modify value, but the result is undefined
    *mutableValue = 100;
    std::cout << "mutableValue: " << *mutableValue << "\n";
}

void library_code() {
    const int value = 10;
    callback(&value);

debbynirwan

void callback(const int *value) {
    int *mutableValue = const_cast<int*>(value);
    // we can now modify value
}

void library_code() {
    int value = 10;
    callback(&value);
}

debbynirwan

void callback(int *value) {
    const int *immutableValue = const_cast<const int*>(value);
    // from this point 
    // we use immutableValue to ensure const correctness
}

void library_code() {
    int value = 10;
    callback(&value);
}

debbynirwan

Output Process(const Input *input) {
    return Output();
}

int main() {
    Input input;
    
    Output output = Process(&input);
    return 0;
}

debbynirwan

int main() {
    Input input;
    const Input *input2 = &input;
    
    Output output = Process(*input2);
    return 0;
}

debbynirwan

Output Process (Input input) {
    return Output();
}

int main() {
    Input input;
    const Input& input2 = input;
    
    Output output = Process(input2);
    return 0;